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공개 퀴즈 목록 (256개 중 101-120)
| ID | 과목 | 파일명 | 문제 수 | 퀴즈 타입 | 소유자 | 통계 조회/가져오기 |
등록일 | 작업 |
|---|---|---|---|---|---|---|---|---|
| 348 | 🔬 Science |
science_quiz4_4_gravity_mass_weight
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 347 | 🔬 Science |
science_quiz4_3_friction_air_resistance
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 346 | 🔬 Science |
science_quiz4_2_newtons_third_law
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 345 | 🔬 Science |
science_quiz4_1_newtons_first_second_laws
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 344 | 🔬 Science |
science_quiz3_8_energy_sustainability
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 343 | 🔬 Science |
science_quiz3_7_fossil_fuels
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 342 | 🔬 Science |
science_quiz3_6_renewable_energy
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 341 | 🔬 Science |
science_quiz3_5_conservation_of_energy
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 340 | 🔬 Science |
science_quiz3_4_work_power_machines
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
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| 339 | 🔬 Science |
science_quiz3_3_heat_transfer
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 338 | 🔬 Science |
science_quiz3_2_energy_transformations
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 337 | 🔬 Science |
science_quiz3_1_forms_of_energy
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 336 | 🔬 Science |
science_quiz2_8_conservation_of_mass
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 335 | 🔬 Science |
science_quiz2_7_redox_reactions
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
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| 334 | 🔬 Science |
science_quiz2_6_oxidation_reduction
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 333 | 🔬 Science |
science_quiz2_5_neutralization
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
| 332 | 🔬 Science |
science_quiz2_4_ph_indicators
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
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| 331 | 🔬 Science |
science_quiz2_3_acids_and_bases
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
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| 330 | 🔬 Science |
science_quiz2_2_types_of_reactions
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25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
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| 329 | 🔬 Science |
science_quiz2_1_chemical_equations
|
25문제 | 🛡️ 교강사 | admin | 👁️ 0 / 📥 0 | 2025-11-25 14:16:20 |
|
📖 science_quiz4_4_gravity_mass_weight
Mass is:
1. How fast object moves
2. How big object is
3. Amount of matter in object ✓
4. Force of gravity on object
Weight is:
1. Amount of matter
2. Force of gravity on object ✓
3. Always constant
4. Same as mass
Unit of mass:
1. Second (s)
2. Kilogram (kg) ✓
3. Meter (m)
4. Newton (N)
Unit of weight:
1. Joule (J)
2. Kilogram (kg)
3. Meter (m)
4. Newton (N) ✓
Your mass on Moon vs. Earth:
1. Zero on Moon
2. Less on Moon
3. Same ✓
4. More on Moon
Your weight on Moon vs. Earth:
1. Less on Moon (about 1/6th) ✓
2. More on Moon
3. Same
4. Zero on Moon
Weight formula:
1. W = mg ✓
2. W = mv
3. W = ma
4. W = ½mv²
What is g on Earth?
1. 10 kg
2. 9.8 m/s² ✓
3. 1 m/s
4. 9.8 N
What does g represent?
1. Gravity constant
2. Gram
3. Acceleration due to gravity ✓
4. Mass
A 5 kg object on Earth (g=9.8 m/s²) weighs:
1. 49 kg
2. 5 N
3. 5 kg
4. 49 N ✓
Object weighs 100 N on Earth. Its mass is:
1. 980 kg
2. 100 kg ✓
3. About 10.2 kg
4. Cannot determine
60 kg person on Moon (g=1.6 m/s²) weighs:
1. 588 N
2. 60 N
3. 96 N ✓
4. 60 kg
Which has strongest gravity (highest g)?
1. Jupiter ✓
2. Moon
3. Mars
4. Earth
Newton's Universal Law of Gravitation states:
1. Gravity only works on Earth
2. Only planets have gravity
3. All masses attract each other ✓
4. Heavier objects fall faster
Gravitational force is proportional to:
1. Sum of masses
2. Ratio of masses
3. Difference of masses
4. Product of masses ✓
Gravitational force is inversely proportional to:
1. Mass squared
2. Distance
3. Distance squared ✓
4. Mass
If distance between two masses doubles, gravitational force:
1. Becomes 1/4 ✓
2. Becomes 1/2
3. Quadruples
4. Doubles
Why don't we feel gravitational attraction to nearby people?
1. We're shielded
2. Gravity doesn't work that way
3. They're too close
4. Their mass is too small ✓
Astronauts in ISS float because:
1. They're in continuous free fall (orbit) ✓
2. There's no gravity there
3. They're too far from Earth
4. They have no weight
Gravity at ISS altitude (~400 km) is:
1. Zero
2. About 10% of surface value
3. Exactly same as surface
4. About 90% of surface value ✓
What is orbit?
1. Moving very slowly
2. Continuous free fall while moving forward ✓
3. Being far from gravity
4. Floating in space
True weightlessness occurs:
1. Underground
2. Far from any mass ✓
3. In orbit
4. On airplane
Do all objects fall at same rate in vacuum?
1. Yes, regardless of mass ✓
2. Only similar masses
3. No, heavier falls faster
4. No, lighter falls faster
On Earth, feather falls slower than rock because:
1. Air resistance affects feather more ✓
2. Feather has less mass
3. Feather is lighter
4. Feather has less gravity
Mass measures:
1. Gravitational force
2. Speed
3. Energy
4. Inertia (resistance to acceleration) ✓
📖 science_quiz4_3_friction_air_resistance
What is friction?
1. Force pulling objects down
2. Force pushing objects up
3. Force opposing motion between surfaces ✓
4. Force making objects accelerate
Friction always acts:
1. Downward only
2. Opposite to direction of motion ✓
3. In direction of motion
4. Perpendicular to motion
Friction is caused by:
1. Gravity
2. Microscopic irregularities in surfaces ✓
3. Air pressure
4. Magnetism
Which has more friction: rubber on concrete or ice on ice?
1. Both equal
2. Ice on ice
3. Neither has friction
4. Rubber on concrete ✓
Friction formula is:
1. Ff = ½mv²
2. Ff = ma
3. Ff = μFN ✓
4. Ff = mgh
What is μ (mu)?
1. Coefficient of friction ✓
2. Mass
3. Velocity
4. Acceleration
Normal force (FN) is:
1. Perpendicular force from surface ✓
2. Gravitational force
3. Parallel force from surface
4. Applied force
Static friction is friction when:
1. Objects are in air
2. Objects are not moving relative to each other ✓
3. Objects are falling
4. Objects are moving
Kinetic friction is friction when:
1. Objects are falling freely
2. Objects are in space
3. Objects are sliding ✓
4. Objects are stationary
Which is typically larger?
1. Both equal
2. Kinetic friction
3. Depends on material only
4. Static friction ✓
Rolling friction compared to sliding friction:
1. Much more
2. Much less ✓
3. Is zero
4. About the same
Does contact area affect friction for solids?
1. Yes, more area = more friction
2. Yes, more area = less friction
3. No, doesn't affect it ✓
4. Only for liquids
To reduce friction, you can:
1. Add lubricant ✓
2. Add more mass
3. Roughen surfaces
4. Increase normal force
To increase friction, you can:
1. Add lubricant
2. Reduce normal force
3. Roughen surfaces ✓
4. Smooth surfaces
Air resistance is:
1. Solid friction
2. Normal force
3. Gravitational force
4. Fluid friction with air ✓
Air resistance increases with:
1. Speed only
2. Mass
3. Speed squared ✓
4. Volume only
Air resistance depends on:
1. Speed, shape, and frontal area ✓
2. Temperature only
3. Mass only
4. Color only
What is terminal velocity?
1. Speed when hitting ground
2. Speed at takeoff
3. Maximum possible speed
4. Constant speed when drag equals weight ✓
Skydiver reaches terminal velocity when:
1. Air resistance equals weight ✓
2. Parachute opens
3. Air resistance equals zero
4. Speed reaches maximum possible
To decrease terminal velocity, skydiver should:
1. Gain mass
2. Make body streamlined
3. Go higher
4. Spread out (increase area) ✓
Streamlined shapes have:
1. No air resistance
2. Same air resistance as any shape ✓
3. Lower air resistance
4. Higher air resistance
Why is it harder to start pushing a heavy box than to keep it moving?
1. Kinetic friction > static friction
2. Static friction > kinetic friction ✓
3. Friction disappears
4. Box gets lighter
Snowshoes prevent sinking because:
1. Large area reduces pressure ✓
2. Small area reduces pressure
3. They eliminate friction
4. They add friction
What percentage of car engine energy is typically lost to friction?
1. About 75% ✓
2. About 10%
3. About 1%
4. 0% (perfect efficiency)
Friction is beneficial for:
1. Perpetual motion
2. Engine efficiency
3. Reducing air resistance
4. Walking and braking ✓
📖 science_quiz4_2_newtons_third_law
Newton's Third Law states:
1. Gravity attracts all masses
2. Objects resist changes in motion
3. For every action, equal and opposite reaction ✓
4. Force equals mass times acceleration
Action-reaction force pairs act on:
1. The same object
2. Different objects ✓
3. Only moving objects
4. Only stationary objects
Action-reaction forces are:
1. Only equal sometimes
2. Equal in magnitude ✓
3. Unequal in magnitude
4. Never equal
Action-reaction forces are:
1. Same direction
2. Perpendicular
3. Random directions
4. Opposite in direction ✓
Why don't action-reaction forces cancel?
1. They're not equal
2. They're not opposite
3. They act on different objects ✓
4. One happens first
When you walk, you push:
1. Backward on ground; ground pushes you forward ✓
2. Down on ground only
3. Sideways on ground
4. Forward on ground; ground pushes you forward
In swimming, you push:
1. Water backward; water pushes you forward ✓
2. Up only
3. Down only
4. Water forward; water pushes you forward
Rocket propulsion works by:
1. Pushing against ground
2. Expelling gas; gas pushes rocket ✓
3. Pushing against air
4. Magic
Do rockets work in space vacuum?
1. Only near planets
2. Only with special fuel
3. Yes, expel their own mass ✓
4. No, need air to push against
When you sit on chair:
1. No forces act
2. Only you push on chair
3. Only chair pushes on you
4. You push down on chair; chair pushes up on you ✓
Earth pulls you down with your weight. You pull Earth:
1. Up with less force
2. Down with equal force ✓
3. Up with equal force
4. Not at all
Why doesn't Earth move noticeably when you pull it?
1. Gravity only works one way
2. Earth is fixed in space
3. Earth's huge mass means tiny acceleration ✓
4. You don't really pull Earth
Two ice skaters push off each other. Forces are:
1. Equal and opposite ✓
2. Greater on lighter skater
3. Greater on heavier skater
4. Unequal and same direction
If 50 kg skater moves at 2 m/s, 100 kg skater moves at:
1. 2 m/s
2. 0.5 m/s (same direction)
3. 1 m/s (opposite direction) ✓
4. 4 m/s
Horse pulls cart. Cart pulls horse. Why do they move?
1. Cart's force is smaller
2. Horse's force is larger
3. They don't really move
4. Forces act on different objects; not balanced on each ✓
Jumping from boat to dock:
1. Only you move
2. Only boat moves
3. You push boat backward; boat pushes you forward ✓
4. You push boat forward; boat pushes you forward
Recoil of gun when fired:
1. Gun pushed backward as bullet goes forward ✓
2. Gun moves forward
3. Gun stays still
4. No forces act
Why does gun recoil less than bullet speed?
1. Friction stops gun
2. Gun has more mass
3. Gun is held firmly
4. Bullet has more mass ✓
Bird flies by:
1. Wings push air down; air pushes wings up ✓
2. Wings create lift magically
3. Wings push forward only
4. Wings push air up; air pushes wings up
Helicopter hovers when:
1. Pilot wants it to
2. Engine is at certain power
3. Blades spin fast enough
4. Downward air push equals weight ✓
Baseball bat hits ball. Forces on bat and ball are:
1. Zero
2. Equal in magnitude ✓
3. Greater on bat
4. Greater on ball
Why does ball go far but bat doesn't fly back?
1. Ball is lighter
2. Bat held by batter (external force) ✓
3. Bat is heavier alone explains it
4. Force on bat is less
Action-reaction pairs:
1. Occur simultaneously ✓
2. Reaction occurs first
3. Action occurs first
4. Have time delay
Hammer hits nail. Nail hits hammer. Result:
1. Both experience same force ✓
2. Nail experiences more
3. Depends on hammer size
4. Hammer experiences more
Newton's Third Law applies:
1. Only to collisions
2. Only on Earth
3. Only when objects touch
4. To all force interactions ✓
📖 science_quiz4_1_newtons_first_second_laws
What is a force?
1. A speed measurement
2. A distance unit
3. A push or pull ✓
4. A type of energy
What is the SI unit of force?
1. Kilogram (kg)
2. Newton (N) ✓
3. Watt (W)
4. Joule (J)
Newton's First Law is also known as:
1. The Law of Acceleration
2. The Law of Inertia ✓
3. The Law of Action-Reaction
4. The Law of Gravity
An object at rest will:
1. Gradually slow down
2. Always start moving eventually
3. Accelerate automatically
4. Stay at rest unless acted on by unbalanced force ✓
An object in motion will:
1. Gradually slow down and stop
2. Speed up automatically
3. Continue in straight line at constant speed unless acted upon ✓
4. Change direction randomly
What is inertia?
1. The tendency to resist changes in motion ✓
2. The force of gravity
3. The speed of an object
4. The mass of an object squared
Which has more inertia?
1. A truck ✓
2. A feather
3. A bicycle
4. A tennis ball
Balanced forces result in:
1. Acceleration
2. No change in motion ✓
3. Change in direction
4. Deceleration
Unbalanced forces cause:
1. No change
2. Zero velocity
3. Acceleration ✓
4. Constant velocity
Newton's Second Law is expressed as:
1. F = mgh
2. F = ½mv²
3. F = mv
4. F = ma ✓
If mass is constant and force doubles:
1. Acceleration stays same
2. Acceleration doubles ✓
3. Acceleration halves
4. Acceleration quadruples
If force is constant and mass doubles:
1. Acceleration halves
2. Acceleration stays same
3. Acceleration doubles ✓
4. Acceleration quadruples
What force is needed to accelerate 10 kg at 5 m/s²?
1. 50 N ✓
2. 5 N
3. 15 N
4. 2 N
A 20 N force acts on 4 kg mass. Acceleration is:
1. 24 m/s²
2. 80 m/s²
3. 5 m/s² ✓
4. 16 m/s²
An object accelerates at 8 m/s² with 40 N force. Its mass is:
1. 48 kg
2. 32 kg
3. 320 kg
4. 5 kg ✓
Net force is:
1. Always zero
2. Always positive
3. Vector sum of all forces ✓
4. Largest force only
Two forces (10 N right, 3 N left) on object. Net force is:
1. 7 N right ✓
2. 7 N left
3. 13 N left
4. 13 N right
When you're in a car that suddenly brakes, you lurch forward because:
1. A forward force pushes you
2. Gravity pulls you forward
3. The car pushes you
4. Your inertia keeps you moving ✓
A hockey puck on frictionless ice:
1. Moves forever at constant speed ✓
2. Changes direction randomly
3. Gradually slows and stops
4. Speeds up
One Newton equals:
1. 1 m/s²
2. 1 kg/s
3. 1 kg·m
4. 1 kg·m/s² ✓
The more mass an object has:
1. The smaller it is
2. The more inertia it has ✓
3. The less inertia it has
4. The faster it moves
If net force is zero, the object:
1. Must be moving only
2. Has constant velocity or is at rest ✓
3. Must be accelerating
4. Must be at rest only
Why do astronauts float in space?
1. They're in continuous free fall (orbit) ✓
2. There's no gravity in space
3. They have no weight or mass
4. They have no mass
A tablecloth is pulled quickly from under dishes. Dishes stay because:
1. Inertia resists sudden change ✓
2. They're glued down
3. Magic
4. Friction is very high
Newton's First and Second Laws apply:
1. Only to large objects
2. Only in laboratories
3. Only on Earth
4. To all objects everywhere ✓
📖 science_quiz3_8_energy_sustainability
What is sustainability?
1. Only environmental protection
2. Never using energy
3. Meeting today's needs without harming future ✓
4. Using all resources now
Three pillars of sustainability:
1. Only environmental
2. Environmental, Social, Economic ✓
3. Only social
4. Only economic
Greenhouse effect is:
1. Only caused by humans
2. Natural process keeping Earth warm ✓
3. Always bad
4. Cooling effect
Main greenhouse gas from energy:
1. Helium
2. Oxygen
3. Nitrogen
4. Carbon dioxide (CO₂) ✓
Energy sector causes what % of emissions?
1. About 10%
2. About 1%
3. About 75% ✓
4. 0%
What is carbon footprint?
1. Total greenhouse gas emissions caused ✓
2. Amount of carbon eaten
3. Carbon in atmosphere
4. Size of feet
Average sustainable carbon footprint target:
1. ~2 tons CO₂/year per person ✓
2. 0.1 tons/year
3. Unlimited
4. 100 tons/year
Energy efficiency means:
1. Using more energy
2. Using less energy for same result ✓
3. Using energy faster
4. Not using energy
Energy conservation means:
1. Destroying energy
2. Creating energy
3. Using energy less often ✓
4. Always using energy
LED bulbs vs incandescent:
1. LEDs less efficient
2. Incandescent better
3. Both equal
4. LEDs 80-90% efficient vs 5% ✓
Best way to reduce home heating energy:
1. Remove insulation
2. Better insulation ✓
3. Use more heaters
4. Open windows
Phantom power refers to:
1. Ghost energy
2. Invisible electricity
3. Devices using energy when 'off' ✓
4. Free energy
Transportation accounts for what % of emissions?
1. ~23% ✓
2. ~50%
3. ~1%
4. ~90%
Electric vehicles are better because:
1. Produce no emissions ever
2. Never need charging
3. Higher efficiency, can use renewable electricity ✓
4. Unlimited range
Paris Agreement goal:
1. Stop all energy use
2. Increase fossil fuels
3. Cool Earth by 5°C
4. Limit warming to 1.5-2°C ✓
What is net zero?
1. Zero economy
2. Zero energy use
3. Emissions produced = emissions removed ✓
4. Zero population
Current global warming:
1. ~1.2°C above pre-industrial ✓
2. No warming
3. ~0.1°C
4. ~10°C
Most effective individual action:
1. Only use paper bags instead of plastic
2. Only recycle materials
3. Do nothing and take no action
4. Reduce car use, improve home energy efficiency, and eat less meat ✓
Renewable energy costs:
1. Decreasing rapidly ✓
2. Staying the same
3. Always increasing
4. More expensive than fossil fuels
Carbon capture and storage (CCS):
1. Releases more CO₂
2. Creates new carbon
3. Captures other gases
4. Captures CO₂ from power plants ✓
Circular economy means:
1. Linear take-make-waste
2. Reduce, reuse, recycle resources ✓
3. Buying more
4. Only throwing away
Energy payback time:
1. Lifetime of device
2. How long to generate energy used in production ✓
3. Time to pay electricity bill
4. Warranty period
Why transition to renewables matters:
1. Climate crisis, air quality, sustainability ✓
2. Use more energy
3. Increase emissions
4. Make energy expensive
Biggest challenge for renewables:
1. Energy storage for intermittent energy sources ✓
2. Renewable energy is too readily available
3. Renewable energy is too inexpensive
4. Renewable energy produces too much power
What gives hope for energy future?
1. Fossil fuels increasing
2. No solutions exist
3. Nothing is changing
4. Technology improving, costs decreasing, awareness growing ✓
📖 science_quiz3_7_fossil_fuels
What are fossil fuels?
1. Solar and wind
2. Nuclear and hydro
3. Coal, oil, and natural gas ✓
4. Geothermal and tidal
Fossil fuels formed from:
1. Water and air
2. Ancient plants and organisms ✓
3. Rocks and minerals
4. Current plants
How long does it take to form fossil fuels?
1. Days
2. Millions of years ✓
3. Months
4. Years
Why are fossil fuels non-renewable?
1. Are being created daily
2. Are infinite
3. Never run out
4. Take millions of years to form ✓
Coal is primarily made of:
1. Oxygen
2. Hydrogen
3. Carbon ✓
4. Nitrogen
Anthracite coal has:
1. Highest carbon content, highest energy ✓
2. No carbon
3. Lowest carbon content
4. Only hydrogen
Oil (petroleum) formed from:
1. Ancient marine organisms ✓
2. Modern algae
3. Coal compression
4. Dinosaurs only
Oil refining separates crude oil into:
1. Compounds by color
2. Different products by boiling point ✓
3. Molecules by size only
4. Elements by weight
Natural gas is primarily:
1. Nitrogen
2. Carbon dioxide
3. Methane (CH₄) ✓
4. Oxygen
Fracking is:
1. Finding oil on surface
2. Cleaning natural gas
3. Making synthetic fuel
4. Fracturing rock to release trapped gas ✓
Main advantage of fossil fuels:
1. Never run out
2. High energy density, convenient ✓
3. No infrastructure needed
4. Completely clean
Main disadvantage of fossil fuels:
1. Too abundant
2. Cold when burned
3. Produce CO₂ causing climate change ✓
4. Renewable
Coal is most used for:
1. Electricity generation ✓
2. Transportation
3. Making plastic
4. Cooking only
Oil is most used for:
1. Electricity only
2. Heating homes only
3. Transportation fuels ✓
4. Agriculture only
Natural gas is cleanest fossil fuel because:
1. Produces no CO₂
2. Has no carbon
3. Is actually renewable
4. Produces ~50% less CO₂ than coal ✓
Estimated fossil fuel reserves:
1. Millions of years
2. Unlimited
3. 50-150 years at current rate ✓
4. Already depleted
What is nuclear energy?
1. Energy from splitting atoms ✓
2. Energy from chemicals
3. Energy from burning uranium
4. Energy from fossils
Nuclear energy advantage:
1. Uses renewable fuel
2. No waste produced
3. Completely safe
4. No CO₂ emissions, very energy-dense ✓
Nuclear energy disadvantage:
1. Radioactive waste, safety concerns ✓
2. Low efficiency
3. Renewable fuel
4. High CO₂ emissions
Major nuclear accidents include:
1. No accidents have ever occurred
2. Hundreds of accidents occur every year
3. Only minor incidents with no significant impact
4. Chernobyl and Fukushima are examples of major accidents ✓
Nuclear fusion (sun's energy):
1. Same as fission
2. Not yet practical for power plants ✓
3. Uses coal
4. Widely used today
Acid rain is caused by:
1. Pure water
2. SO₂ and NOₓ from burning fossil fuels ✓
3. Nuclear energy
4. Renewable energy
Ocean acidification caused by:
1. CO₂ absorbed from atmosphere ✓
2. Too much salt
3. Marine life
4. Natural processes only
Peak oil means:
1. Maximum oil production rate has passed ✓
2. Oil is unlimited
3. Oil is most expensive
4. Oil is at highest quality
Bridge fuel refers to:
1. Nuclear only
2. Renewable energy
3. Coal power
4. Natural gas (cleaner than coal, not renewable) ✓
📖 science_quiz3_6_renewable_energy
What is renewable energy?
1. Energy that lasts forever
2. Energy from fossil fuels
3. Energy from naturally replenished sources ✓
4. Energy from nuclear
Which is renewable energy?
1. Coal, oil, gas
2. Solar, wind, hydro ✓
3. All fossil fuels
4. Uranium
How do solar panels work?
1. Store sunlight
2. Convert sunlight to electricity ✓
3. Reflect sunlight
4. Burn sunlight
Solar panel efficiency is typically:
1. 80-90%
2. 100%
3. 5%
4. 15-20% ✓
Advantage of solar energy:
1. Works at night
2. Small scale only
3. Clean, no emissions, unlimited ✓
4. Very cheap initially
Disadvantage of solar energy:
1. Intermittent (doesn't work at night) ✓
2. Causes pollution
3. Heats the planet
4. Very loud
Wind turbines generate electricity by:
1. Converting kinetic energy of wind ✓
2. Stopping wind
3. Burning wind
4. Creating wind
Wind energy advantage:
1. Silent operation
2. Clean, renewable, land can be used below ✓
3. Works without wind
4. Cheap to build
Wind energy disadvantage:
1. Produces CO₂
2. Causes earthquakes
3. Intermittent, location-specific, can harm birds ✓
4. Uses too much water
Hydroelectric power uses:
1. Thermal energy of water
2. Nuclear energy
3. Chemical energy in water
4. Potential energy of water at height ✓
Hydroelectric power advantage:
1. Very small scale
2. Reliable, very efficient (~90%) ✓
3. No environmental impact
4. Works without water
Hydroelectric power disadvantage:
1. Very inefficient
2. Causes air pollution
3. Can disrupt ecosystems, location-specific ✓
4. Produces CO₂
Geothermal energy uses:
1. Heat from Earth's interior ✓
2. Heat from sun
3. Heat from friction
4. Heat from combustion
Geothermal advantage:
1. No drilling needed
2. Very cheap
3. 24/7 reliable, small footprint ✓
4. Available everywhere
Geothermal disadvantage:
1. Very loud
2. Cools the Earth
3. Produces lots of CO₂
4. Location-specific (near tectonic boundaries) ✓
Biomass energy comes from:
1. Synthetic materials
2. Rocks and minerals
3. Organic matter (plants, waste) ✓
4. Metal ores
Biomass is considered renewable because:
1. Plants regrow and absorb CO₂ ✓
2. It's very efficient
3. It's free
4. It never runs out
Biomass disadvantage:
1. Works anywhere
2. 100% efficient
3. Completely clean
4. Can compete with food production ✓
Tidal energy uses:
1. Movement of ocean tides ✓
2. Ocean temperature
3. Ocean color
4. Salt in seawater
Tidal energy advantage:
1. Very cheap
2. No environmental impact
3. Available everywhere
4. Very predictable ✓
Which renewable has highest capacity factor?
1. Solar energy with a relatively low capacity factor
2. Geothermal energy with a very high capacity factor ✓
3. Wind energy with a moderate capacity factor
4. Tidal energy with a moderate capacity factor
Why is energy storage important for renewables?
1. To make renewable energy more expensive
2. To destroy excess energy that is produced
3. Solar and wind energy sources are intermittent ✓
4. To create more energy than is available
Pumped hydro storage:
1. Pumps water uphill to store energy ✓
2. Uses chemical reactions
3. Creates new water
4. Destroys energy
Iceland gets most energy from:
1. Geothermal energy, which is abundant in Iceland ✓
2. Nuclear power plants
3. Oil and petroleum products
4. Coal-fired power plants
Best renewable energy solution:
1. All solar
2. Only one type
3. All wind
4. Mix of different sources ✓
📖 science_quiz3_5_conservation_of_energy
The law of conservation of energy states:
1. Energy always increases
2. Energy can be destroyed
3. Energy cannot be created or destroyed ✓
4. Energy can be created
What is an isolated system?
1. Energy freely flows
2. No energy enters or leaves ✓
3. Only energy enters
4. Only energy leaves
Total energy in isolated system:
1. Always increases
2. Remains constant ✓
3. Always decreases
4. Varies randomly
In a pendulum (no friction), total mechanical energy:
1. Decreases
2. Increases
3. Becomes zero
4. Stays constant ✓
At top of pendulum swing:
1. Maximum KE, zero PE
2. Equal PE and KE
3. Maximum PE, zero KE ✓
4. Both zero
At bottom of pendulum swing:
1. Maximum KE, minimum PE ✓
2. Equal PE and KE
3. Both zero
4. Maximum PE, zero KE
A ball dropped from 10 m. Just before ground:
1. All PE converted to KE ✓
2. Energy disappears
3. Energy is destroyed
4. Only PE exists
Where does 'lost' energy go?
1. Is actually destroyed
2. Transforms to heat/sound (not truly lost) ✓
3. Returns to source
4. Disappears into space
Bouncing ball loses height because:
1. Gravity gets stronger
2. Ball loses mass
3. Energy converts to heat and sound ✓
4. Energy is destroyed
Friction seems to 'destroy' mechanical energy, but:
1. Actually destroys it
2. Stores it forever
3. Reverses time
4. Converts it to thermal energy ✓
Why do roller coasters need first hill highest?
1. To go faster
2. Energy conserved; can't gain more energy ✓
3. For fun
4. For safety
Perpetual motion machine is impossible because:
1. Not enough materials
2. Not invented yet
3. Energy is always lost to heat/friction ✓
4. Gravity prevents it
If you lift 2 kg to 5 m, then drop it. Final KE equals:
1. Initial PE (if no air resistance) ✓
2. Less than initial PE always
3. Zero
4. More than initial PE
System with friction:
1. Energy disappears
2. Energy is destroyed
3. Total energy conserved (includes heat) ✓
4. Energy multiplies
In car braking, kinetic energy becomes:
1. Light energy
2. Chemical energy
3. Nuclear energy
4. Thermal energy in brakes ✓
Spring compressed then released. Energy transformations:
1. Nuclear → Thermal
2. KE → Chemical
3. Elastic PE → KE → Other forms ✓
4. Light → Sound
A 1000 kg car at 20 m/s brakes to stop. KE becomes:
1. 200,000 J of thermal energy ✓
2. Stays as KE
3. Becomes PE
4. Is destroyed
Why can't we collect all 'wasted' energy?
1. It's destroyed
2. It's invisible
3. It goes to space
4. It spreads out and becomes unusable (entropy) ✓
E = mc² shows:
1. Mass can convert to energy ✓
2. Energy = motion × speed
3. Energy = mass × charge
4. Energy = momentum × mass
Nuclear reactions release energy by:
1. Destroying energy
2. Creating energy from nothing
3. Chemical reactions
4. Converting small amount of mass to energy ✓
Hydroelectric dam stores energy as:
1. Nuclear energy
2. Gravitational PE ✓
3. Kinetic energy
4. Chemical energy
Pumped-storage hydroelectricity:
1. Destroys energy
2. Stores energy by pumping water uphill ✓
3. Creates new energy
4. Uses fusion
If total energy is conserved, why energy crisis?
1. Useful energy becomes less useful (entropy) ✓
2. Energy leaves Earth
3. Not enough energy exists
4. Energy is destroyed
Regenerative braking in electric cars:
1. Converts KE back to electrical energy ✓
2. Creates new energy
3. Destroys kinetic energy
4. Uses only friction
Conservation of energy applies:
1. Only on Earth
2. Only to large objects
3. Only in laboratories
4. Everywhere in the universe ✓
📖 science_quiz3_4_work_power_machines
What is work in physics?
1. Any physical activity
2. Energy stored in object
3. Force applied over a distance ✓
4. Power multiplied by time
Work formula is:
1. W = P × t
2. W = F × d ✓
3. W = ½mv²
4. W = m × a
SI unit of work is:
1. Pascal (Pa)
2. Joule (J) ✓
3. Watt (W)
4. Newton (N)
Is work done when carrying a box horizontally?
1. Yes, you're tired
2. Yes, you're carrying weight
3. Yes, box is heavy
4. No, force perpendicular to motion ✓
What is power?
1. Distance per time
2. Total energy
3. Rate of doing work ✓
4. Amount of force
Power formula is:
1. P = W / t ✓
2. P = m × a
3. P = ½mv²
4. P = F × d
SI unit of power is:
1. Watt (W) ✓
2. Meter (m)
3. Newton (N)
4. Joule (J)
One watt equals:
1. One meter per second
2. One joule per second ✓
3. One kilogram meter
4. One newton per meter
Two people lift same box to same height. One does it faster. Who has more power?
1. Neither has power
2. The slower person
3. The faster person ✓
4. Both have same power
What is a simple machine?
1. Device that destroys friction
2. Device that creates energy
3. Device that reduces work
4. Device that makes work easier ✓
Simple machines reduce total work needed. True or false?
1. True - energy is saved
2. False - work stays the same ✓
3. False - work increases
4. True - work is reduced
What is mechanical advantage (MA)?
1. Distance / Force
2. Input force / Output force
3. Output force / Input force ✓
4. Work / Time
If MA = 4, what does it mean?
1. Output force is 4× input force ✓
2. 4 joules of work
3. Input force is 4× output
4. 4 machines needed
Trade-off in simple machines:
1. More speed means less work
2. Less distance gives more force
3. Less force requires more distance ✓
4. More force requires less energy
Name the six simple machines:
1. None of these options are correct
2. Hammer, saw, drill, lathe, press, and jack
3. Car, bike, train, plane, boat, and rocket
4. Lever, wheel and axle, pulley, inclined plane, wedge, and screw ✓
A lever has three parts:
1. Handle, pivot, base
2. Motor, gear, shaft
3. Fulcrum, effort, load ✓
4. Spring, force, mass
In a Class 1 lever:
1. Fulcrum is in the middle ✓
2. Effort is in the middle
3. Load is in the middle
4. All are same point
Wheelbarrow is which class lever?
1. Class 1 (fulcrum in middle)
2. Class 3 (effort in middle)
3. Not a lever
4. Class 2 (load in middle) ✓
A fixed pulley provides:
1. MA = 1 (changes direction only) ✓
2. MA = 2
3. MA = 4
4. MA = 0
Movable pulley provides:
1. MA = 4
2. MA = 0
3. MA = 1
4. MA = 2 ✓
Inclined plane MA formula:
1. Height / Length
2. Length of ramp / Height ✓
3. Force / Distance
4. Mass × gravity
Wedge is made of:
1. One screw
2. Two inclined planes back-to-back ✓
3. One pulley
4. One lever
Screw is:
1. Inclined plane wrapped around cylinder ✓
2. Rotating wedge
3. Spinning pulley
4. Lever in circle
If you push 100 N with MA = 5, output force is:
1. 500 N ✓
2. 5 N
3. 20 N
4. 100 N
Why are machines less than 100% efficient?
1. Work is lost
2. Energy is destroyed
3. Machines create energy
4. Friction converts energy to heat ✓
📖 science_quiz3_3_heat_transfer
What is the difference between heat and temperature?
1. Heat is always higher
2. They are the same thing
3. Heat is energy transfer; temperature is average KE ✓
4. Temperature transfers energy
Heat always flows from:
1. Cold to hot
2. Hot to cold ✓
3. High to low density
4. Low to high pressure
What is thermal equilibrium?
1. When temperature is zero
2. When two objects reach same temperature ✓
3. When heat stops existing
4. When cold wins over hot
What is conduction?
1. Heat transfer through light
2. Heat transfer through fluid motion
3. Heat transfer through empty space
4. Heat transfer through direct contact ✓
Which material is the best conductor?
1. Air
2. Plastic
3. Silver ✓
4. Wood
Which material is the best insulator?
1. Air ✓
2. Copper
3. Aluminum
4. Steel
What is convection?
1. Heat transfer through fluid movement ✓
2. Heat transfer through sound
3. Heat transfer through radiation
4. Heat transfer through solid contact
In convection, warm fluid:
1. Moves randomly
2. Rises because it's less dense ✓
3. Stays in place
4. Sinks because it's heavier
What is radiation?
1. Heat transfer through touching
2. Heat transfer through sound
3. Heat transfer through electromagnetic waves ✓
4. Heat transfer through water
Which heat transfer method works in vacuum?
1. All three methods
2. Convection only
3. Conduction only
4. Radiation only ✓
The sun heats Earth through:
1. Convection
2. Radiation ✓
3. All three
4. Conduction
Metal feels colder than wood at same temperature because:
1. Metal contains ice
2. Wood has higher temperature
3. Metal conducts heat away faster ✓
4. Metal is actually colder
Boiling water shows heat transfer by:
1. Convection ✓
2. Reflection
3. Conduction
4. Radiation
A thermos flask reduces heat transfer by:
1. Using solid metal walls
2. Allowing air circulation
3. Eliminating conduction and convection ✓
4. Increasing thermal conductivity
Dark colors absorb radiation:
1. Same as light colors
2. Not at all
3. Worse than light colors
4. Better than light colors ✓
Why do hot air balloons rise?
1. Hot air is magnetic
2. Hot air is compressed
3. Hot air is less dense (convection) ✓
4. Hot air weighs more
Sea breeze during day occurs because:
1. Land heats faster than water, causing air to rise through convection ✓
2. Gravity pulls air downward
3. Wind comes from outer space
4. Ocean is always cold throughout the day
Which has highest thermal conductivity?
1. Wood
2. Styrofoam
3. Glass
4. Copper ✓
Home insulation works by:
1. Trapping air to prevent convection ✓
2. Creating heat
3. Reflecting all radiation
4. Increasing conduction
Wearing multiple layers in cold keeps you warm by:
1. Creating body heat
2. Blocking all radiation
3. Increasing conduction
4. Trapping air between layers ✓
Which material would you use for pot handles?
1. Metal (conductors)
2. Wood or plastic (insulators) ✓
3. Glass
4. Ice
Infrared cameras detect:
1. Magnetic fields
2. Thermal radiation from objects ✓
3. Sound waves
4. X-rays
Why does a fan help you cool down?
1. Increases convection (air movement) ✓
2. Stops radiation
3. Creates ice
4. Decreases air temperature
Double-pane windows reduce heat loss by:
1. Trapping air between panes ✓
2. Increasing conduction
3. Eliminating glass
4. Using metal frames
At night, Earth cools by:
1. All equally
2. Conduction to air
3. Convection in atmosphere
4. Radiating heat to space ✓
📖 science_quiz3_2_energy_transformations
What is energy transformation?
1. Storing energy forever
2. Creating new energy
3. Changing energy from one form to another ✓
4. Destroying old energy
Energy transformation vs. energy transfer?
1. Transfer only in solids
2. Transformation = form changes; Transfer = location changes ✓
3. Transformation is faster
4. They mean the same thing
In a flashlight: Battery → Light. What transformations?
1. Kinetic energy transforms directly to light
2. Chemical energy transforms to electrical energy, then to light and thermal energy ✓
3. Mechanical energy transforms directly to light
4. Nuclear energy transforms directly to light
Law of conservation of energy states:
1. Energy can be destroyed
2. Energy always increases
3. Energy can be created
4. Energy cannot be created or destroyed ✓
Photosynthesis transforms which energies?
1. Nuclear → Light
2. Kinetic → Chemical
3. Light → Chemical ✓
4. Chemical → Light
When you eat and move, what transformation?
1. Chemical → Kinetic + Thermal ✓
2. Nuclear → Kinetic
3. Light → Kinetic
4. Kinetic → Chemical
Hydroelectric dam: Water → Electricity
1. Potential → Kinetic → Electrical ✓
2. Nuclear → Electrical
3. Thermal → Electrical
4. Chemical → Electrical
What is a Sankey diagram used for?
1. Determining mass
2. Showing energy flow and efficiency ✓
3. Calculating velocity
4. Measuring temperature
If device is 80% efficient, what happens to 20%?
1. Stored in device
2. Becomes useful energy
3. Lost as waste heat ✓
4. Destroyed
Solar panel efficiency is typically:
1. 100%
2. 80-90%
3. 5-10%
4. 15-20% ✓
Car engine is 25% efficient. Where does energy go?
1. 75% in fuel tank
2. 75% becomes heat ✓
3. 75% is destroyed
4. 75% becomes sound only
What is efficiency formula?
1. Force × Distance
2. Total / Useful
3. Useful energy out / Total energy in × 100% ✓
4. Power / Time
Why is no device 100% efficient?
1. Friction always causes heat loss ✓
2. Not enough technology
3. Energy is destroyed
4. Physics prevents it
LED vs incandescent: Which is more efficient?
1. Neither produces light at all
2. Both are equally efficient
3. LED bulbs are much more efficient than incandescent bulbs ✓
4. Incandescent bulbs are more efficient
In a pendulum, energy transforms between:
1. Light and sound
2. Electrical and magnetic
3. Chemical and nuclear
4. Potential and kinetic ✓
Cellular respiration transforms:
1. Light → Chemical
2. Nuclear → Chemical
3. Chemical (glucose) → ATP + Thermal ✓
4. Kinetic → Chemical
Input 500 J, output 400 J, efficiency is:
1. 80% ✓
2. 100%
3. 20%
4. 125%
Energy chains show:
1. Energy being created
2. Only one transformation
3. Energy being destroyed
4. Multiple transformations in sequence ✓
Coal power plant energy chain:
1. Chemical energy transforms to thermal, then kinetic, then electrical energy ✓
2. Chemical energy transforms directly to electrical energy
3. Nuclear energy transforms directly to electrical energy
4. Solar energy transforms directly to electrical energy
What reduces energy efficiency in machines?
1. Perfect surfaces
2. Vacuum conditions
3. Too much input
4. Friction and air resistance ✓
Electric motor 90% efficient, 1000 J input. Output?
1. 500 J each
2. 900 J useful, 100 J heat ✓
3. 100 J useful, 900 J heat
4. 1000 J useful, 0 J heat
Microwave oven transformation:
1. Chemical energy transforms directly to thermal energy
2. Electrical energy transforms to electromagnetic energy, then to thermal energy ✓
3. Kinetic energy transforms directly to thermal energy
4. Nuclear energy transforms directly to thermal energy
Energy 'loss' in transformations means:
1. Converts to less useful forms (heat) ✓
2. Decreases in amount
3. Is actually destroyed
4. Disappears completely
Bouncing ball loses height each bounce because:
1. Energy converts to heat and sound ✓
2. Mass decreases
3. Energy is destroyed
4. Gravity increases
Which has best transformation efficiency?
1. Incandescent bulb (5%)
2. Car engine (25%)
3. Human body (20%)
4. Electric motor (85-90%) ✓
📖 science_quiz3_1_forms_of_energy
What is energy?
1. The force of gravity
2. The mass of matter
3. The ability to do work or cause change ✓
4. The speed of an object
Which type of energy is stored in food?
1. Kinetic energy
2. Chemical energy ✓
3. Sound energy
4. Light energy
A moving car has which type of energy?
1. Nuclear energy
2. Kinetic energy ✓
3. Potential energy
4. Chemical energy
What formula represents kinetic energy?
1. KE = mc²
2. KE = mgh
3. KE = Fd
4. KE = ½mv² ✓
A book on a high shelf has what type of energy?
1. Sound energy
2. Thermal energy
3. Gravitational potential energy ✓
4. Kinetic energy
Which energy form is associated with temperature?
1. Thermal energy ✓
2. Nuclear energy
3. Electrical energy
4. Potential energy
What is the SI unit of energy?
1. Joule (J) ✓
2. Meter (m)
3. Newton (N)
4. Watt (W)
Sunlight is an example of which energy form?
1. Elastic potential energy
2. Light/radiant energy ✓
3. Kinetic energy
4. Chemical energy
A stretched rubber band stores which energy?
1. Chemical energy
2. Kinetic energy
3. Elastic potential energy ✓
4. Nuclear energy
Which has the most kinetic energy?
1. A slow-moving bicycle
2. A parked airplane
3. A stationary car
4. A fast-moving truck ✓
What happens to KE when velocity doubles?
1. It doubles
2. It quadruples ✓
3. It halves
4. It stays the same
Batteries store which form of energy?
1. Light energy
2. Sound energy
3. Chemical energy ✓
4. Kinetic energy
Lightning is an example of which energy?
1. Electrical energy ✓
2. Nuclear energy
3. Mechanical energy
4. Thermal energy
What type of energy does a nuclear power plant use?
1. Solar energy
2. Chemical energy
3. Nuclear energy ✓
4. Wind energy
A vibrating guitar string produces what energy?
1. Nuclear energy
2. Chemical energy
3. Gravitational energy
4. Sound energy ✓
Which object has gravitational potential energy?
1. Wind blowing horizontally
2. A car moving at constant speed
3. Water at the top of a waterfall ✓
4. A rolling ball on flat ground
What energy transformation occurs in a light bulb?
1. Electrical → Light + Thermal ✓
2. Kinetic → Light
3. Chemical → Light
4. Nuclear → Light
A falling apple has which energies?
1. Only kinetic energy
2. Only potential energy
3. Neither type
4. Both potential and kinetic ✓
What is the potential energy formula?
1. PE = mgh ✓
2. PE = Fd
3. PE = ½mv²
4. PE = mc²
Energy can be created or destroyed. True or false?
1. True - energy can be destroyed
2. False - energy is conserved ✓
3. False - energy disappears
4. True - energy can be created
A compressed spring stores what energy?
1. Chemical energy
2. Elastic potential energy ✓
3. Nuclear energy
4. Sound energy
What energy does your body primarily use?
1. Solar energy
2. Chemical energy from food ✓
3. Nuclear energy
4. Electrical energy
A 2 kg ball is 5 m high. What is its PE? (g = 10 m/s²)
1. 100 J ✓
2. 200 J
3. 50 J
4. 10 J
Which has more PE: 1 kg at 10 m or 2 kg at 5 m?
1. 1 kg at 10 m ✓
2. Cannot determine
3. 2 kg at 5 m
4. Both have the same
Can an object have multiple forms of energy simultaneously?
1. No, never
2. Only in special cases
3. Only two types maximum
4. Yes, always possible ✓
📖 science_quiz2_8_conservation_of_mass
Who established the Law of Conservation of Mass?
1. Isaac Newton
2. John Dalton
3. Antoine Lavoisier ✓
4. Albert Einstein
What does the Law of Conservation of Mass state?
1. Mass can be created
2. Mass is neither created nor destroyed ✓
3. Mass always increases
4. Mass always decreases
In a chemical reaction, the total mass of reactants must equal the total mass of:
1. Atoms
2. Products ✓
3. Molecules
4. Electrons
Why is mass conserved in chemical reactions?
1. Atoms change identity
2. Atoms are multiplied
3. Atoms disappear
4. Atoms are rearranged, not created or destroyed ✓
What is a closed system?
1. A system with no reactions
2. A system with gases only
3. A system where no matter enters or leaves ✓
4. A system at low temperature
What is an open system?
1. A system where matter can enter or leave ✓
2. A system at high pressure
3. A system with only liquids
4. A system with no products
If 24 g of magnesium reacts with 16 g of oxygen, what is the mass of magnesium oxide formed?
1. 40 g ✓
2. 24 g
3. 16 g
4. 8 g
When 10 g of calcium carbonate decomposes to 5.6 g of calcium oxide, what mass of CO2 is released?
1. 15.6 g
2. 4.4 g ✓
3. 5.6 g
4. 10 g
Why does mass appear to increase when magnesium burns in air?
1. Light adds mass
2. Magnesium expands
3. Oxygen from air is incorporated ✓
4. Heat adds mass
Why does mass appear to decrease when calcium carbonate is heated in an open container?
1. Oxygen is absorbed
2. Calcium evaporates
3. Heat destroys mass
4. CO2 gas escapes ✓
In a balanced chemical equation, the number of each type of atom on the left must:
1. Be less than the right
2. Equal the number on the right ✓
3. Be greater than the right
4. Be unrelated
If 4 g of hydrogen reacts with 32 g of oxygen to form water, what is the mass of water produced?
1. 28 g
2. 4 g
3. 36 g ✓
4. 32 g
What did Lavoisier use to prove the Law of Conservation of Mass?
1. Sealed containers ✓
2. Open beakers
3. Bunsen burners
4. Test tubes
In the reaction 2H2 + O2 -> 2H2O, how many atoms are there in total before the reaction?
1. 3
2. 4
3. 5 ✓
4. 6
In the reaction 2H2 + O2 -> 2H2O, how many atoms are there in total after the reaction?
1. 4
2. 3
3. 8
4. 6 ✓
When wood burns in an open fire, where does most of the mass go?
1. It disappears
2. Into light
3. Into CO2 and H2O vapor (gases) ✓
4. Into heat
What is the relationship between balanced equations and conservation of mass?
1. Balanced equations reflect conservation of mass ✓
2. Balanced equations violate conservation
3. No relationship
4. They oppose each other
In a truly closed system, can mass change during a chemical reaction?
1. Yes, only for solids
2. Yes, only for gases
3. Yes, always
4. No, mass is conserved ✓
If 100 g of reactants produce 98 g of solid products in an open container, what likely happened?
1. 2 g of gas escaped ✓
2. Mass was destroyed
3. The scale was wrong
4. Mass was converted to energy
Why is conservation of mass important in industrial chemistry?
1. It is not important
2. Only for research
3. Only for safety
4. To calculate raw materials and products accurately ✓
In space missions, why is conservation of mass crucial?
1. It prevents explosions
2. All resources must be accounted for and recycled ✓
3. Rockets need extra mass
4. Space has no mass
In the equation Fe + O2 -> Fe2O3, why must it be balanced?
1. To make it longer
2. To reflect that atoms (and thus mass) are conserved ✓
3. To add complexity
4. To look neat
What happens to the mass of a sealed container when a reaction occurs inside?
1. It stays the same ✓
2. It increases
3. It decreases
4. It doubles
If a candle burns in a sealed jar, what happens to the total mass of the jar and its contents?
1. It stays the same ✓
2. It becomes zero
3. It decreases
4. It increases
Einsteins equation E=mc^2 shows that:
1. Energy is always destroyed
2. Mass and energy are unrelated
3. Mass is always created
4. Mass and energy are related ✓
📖 science_quiz2_7_redox_reactions
What does REDOX stand for?
1. Reactive Oxygen
2. Red Oxide
3. Reduction-Oxidation ✓
4. Reduced Oxygen
What is a half-reaction?
1. Half of a molecule
2. An equation showing only oxidation or only reduction ✓
3. An incomplete reaction
4. A weak reaction
In the half-reaction Zn -> Zn2+ + 2e-, what is happening?
1. Reduction
2. Oxidation ✓
3. Neutralization
4. Decomposition
In the half-reaction Cu2+ + 2e- -> Cu, what is happening?
1. Oxidation
2. Synthesis
3. Neutralization
4. Reduction ✓
In a redox reaction, electrons lost must equal electrons:
1. Remaining
2. Created
3. Gained ✓
4. Destroyed
Which type of reaction is NOT a redox reaction?
1. Double replacement (like neutralization) ✓
2. Single replacement
3. Combination
4. Combustion
In the reaction 2Mg + O2 -> 2MgO, what is oxidized?
1. Magnesium ✓
2. MgO
3. Nothing
4. Oxygen
In photosynthesis, carbon in CO2 is:
1. Unchanged
2. Reduced ✓
3. Neutralized
4. Oxidized
In cellular respiration, glucose is:
1. Unchanged
2. Reduced
3. Oxidized ✓
4. Neutralized
Photosynthesis and cellular respiration are:
1. The same reaction
2. Both oxidation only
3. Unrelated
4. Opposite reactions ✓
In a battery, oxidation occurs at the:
1. Electrolyte
2. Anode ✓
3. Wire
4. Cathode
In a battery, reduction occurs at the:
1. Electrolyte
2. Wire
3. Cathode ✓
4. Anode
Electrolysis uses:
1. Electrical energy to drive chemical reactions ✓
2. No energy
3. Heat energy only
4. Chemical energy to produce electricity
In the extraction of iron (Fe2O3 + 3CO -> 2Fe + 3CO2), what is reduced?
1. Oxygen
2. Carbon
3. Iron ✓
4. CO2
In rusting, iron is:
1. Melted
2. Reduced
3. Frozen
4. Oxidized ✓
Antioxidants work by:
1. Speeding up reactions
2. Adding oxygen
3. Preventing oxidation ✓
4. Causing oxidation
Which is an example of a redox reaction?
1. CH4 + 2O2 -> CO2 + 2H2O ✓
2. All of the above
3. NaCl + AgNO3 -> AgCl + NaNO3
4. HCl + NaOH -> NaCl + H2O
In steel production, carbon acts as a:
1. Neutralizing agent
2. Catalyst
3. Oxidizing agent
4. Reducing agent ✓
Galvanizing prevents rust by:
1. Coating with zinc that oxidizes first ✓
2. Adding oxygen
3. Painting iron
4. Removing all air
Chlorine bleach works by:
1. Reducing colored compounds
2. Neutralizing acids
3. Dissolving stains
4. Oxidizing colored compounds ✓
Free radicals are:
1. Weak acids
2. Highly reactive oxidizing agents ✓
3. Always harmless
4. Only found in plants
Which is a way to prevent food oxidation?
1. Adding water
2. Vacuum packaging ✓
3. Adding oxygen
4. Heating to 100 degrees C continuously
In the nitrogen cycle, conversion of N2 to NH3 is:
1. Reduction ✓
2. Neutralization
3. Combustion
4. Oxidation
Acid rain formation involves:
1. Oxidation of sulfur and nitrogen compounds ✓
2. Only reduction
3. No redox reactions
4. Only neutralization
In electrolysis of water, hydrogen gas is produced by:
1. Combustion
2. Neutralization
3. Oxidation
4. Reduction ✓
📖 science_quiz2_6_oxidation_reduction
What is oxidation in terms of electrons?
1. No change in electrons
2. Gain of electrons
3. Loss of electrons ✓
4. Sharing electrons
What is reduction in terms of electrons?
1. No change
2. Gain of electrons ✓
3. Sharing electrons
4. Loss of electrons
What does OIL RIG stand for?
1. Only Ions Leave, Rest Is Gained
2. Oxidation Is Loss, Reduction Is Gain ✓
3. Oxygen Is Light, Reduction Is Great
4. Oil In Life, Really Important Gas
In the reaction Zn + Cu2+ -> Zn2+ + Cu, what happens to zinc?
1. It is reduced
2. It decomposes
3. It stays the same
4. It is oxidized ✓
In the reaction Zn + Cu2+ -> Zn2+ + Cu, what happens to copper ions?
1. They decompose
2. They are oxidized
3. They are reduced ✓
4. They stay the same
What is an oxidizing agent?
1. A substance that causes oxidation and is itself reduced ✓
2. A substance that loses oxygen
3. A substance that is oxidized
4. A substance that prevents oxidation
What is a reducing agent?
1. A substance that causes reduction and is itself oxidized ✓
2. A substance that gains oxygen
3. A substance that prevents reduction
4. A substance that is reduced
When iron rusts (4Fe + 3O2 -> 2Fe2O3), what happens to iron?
1. It evaporates
2. It is oxidized ✓
3. It is reduced
4. Nothing
Historically, oxidation meant:
1. Losing oxygen
2. Gaining electrons
3. Combining with oxygen ✓
4. Losing hydrogen
What is the oxidation state of a free element like O2 or Fe?
1. +1
2. Variable
3. -2
4. 0 ✓
What is the usual oxidation state of oxygen in compounds?
1. +2
2. -2 ✓
3. -1
4. 0
What is the usual oxidation state of hydrogen in compounds?
1. +2
2. -1
3. +1 ✓
4. 0
In the reaction CuO + H2 -> Cu + H2O, what is reduced?
1. Copper oxide ✓
2. Water
3. Nothing
4. Hydrogen
If oxidation state increases, the substance is:
1. Reduced
2. Neutral
3. Oxidized ✓
4. Decomposed
If oxidation state decreases, the substance is:
1. Neutral
2. Oxidized
3. Synthesized
4. Reduced ✓
Do oxidation and reduction always occur together?
1. Only in acids
2. Only in bases
3. Yes, they always occur together ✓
4. No, they are independent
Cellular respiration involves:
1. Both oxidation and reduction ✓
2. Only reduction
3. Only oxidation
4. Neither process
In batteries, what happens at the anode?
1. Combustion
2. Neutralization
3. Reduction
4. Oxidation ✓
Which is a common oxidizing agent?
1. Oxygen ✓
2. Zinc
3. Hydrogen
4. Carbon
Which is a common reducing agent?
1. Chlorine
2. Nitric acid
3. Oxygen
4. Hydrogen ✓
Galvanizing iron with zinc prevents rust because:
1. Zinc is prettier
2. Zinc oxidizes first, protecting iron ✓
3. Zinc prevents oxygen contact
4. Zinc makes iron harder
Antioxidants in food:
1. Add oxygen
2. Prevent oxidation ✓
3. Cause reduction
4. Speed up oxidation
In photosynthesis, carbon in CO2 is:
1. Reduced ✓
2. Eliminated
3. Neutralized
4. Oxidized
Bleach works by:
1. Oxidizing colored compounds ✓
2. Reducing stains
3. Dissolving dirt
4. Adding color
What is the oxidation state of sulfur in H2SO4?
1. +2
2. +4
3. -2
4. +6 ✓
📖 science_quiz2_5_neutralization
What is a neutralization reaction?
1. Base + Metal -> Salt
2. Acid + Metal -> Salt + Hydrogen
3. Acid + Base -> Salt + Water ✓
4. Acid + Acid -> Salt
What are the two products of a neutralization reaction?
1. Acid and base
2. Salt and water ✓
3. Gas and water
4. Metal and salt
What is the equation for HCl + NaOH?
1. Na2Cl + H2O
2. NaCl + H2O ✓
3. NaH + ClOH
4. NaCl + H2
What is a salt in chemistry?
1. Only NaCl
2. Always a liquid
3. A type of acid
4. An ionic compound from neutralization ✓
Which is a common salt used in food?
1. NaOH
2. CaCO3
3. NaCl (sodium chloride) ✓
4. H2SO4
What salt is formed from H2SO4 + 2NaOH?
1. Na2SO4 ✓
2. Na2S
3. NaS
4. NaSO4
What happens to pH during neutralization of an acid?
1. pH increases toward 7 ✓
2. pH goes to 14
3. pH decreases
4. pH stays at 0
At the equivalence point of a strong acid-strong base titration, what is the pH?
1. 0
2. 7 ✓
3. 3
4. 14
What is titration used for?
1. Producing water
2. Measuring temperature
3. Determining unknown concentration ✓
4. Making salt
Which piece of equipment delivers precise volumes of solution during titration?
1. Pipette only
2. Test tube
3. Beaker
4. Burette ✓
What is the purpose of an indicator in titration?
1. To neutralize the acid
2. To show when neutralization is complete ✓
3. To heat the solution
4. To produce salt
Which indicator is commonly used in strong acid-strong base titrations?
1. Methyl orange
2. Universal indicator
3. Phenolphthalein ✓
4. Litmus
Neutralization reactions are:
1. Exothermic ✓
2. Endothermic
3. Neither
4. Cold
What is the heat of neutralization for H+ + OH- -> H2O?
1. About -100 kJ/mol
2. About +57 kJ/mol
3. About -57 kJ/mol ✓
4. 0 kJ/mol
Antacids work by:
1. Killing bacteria only
2. Dissolving food
3. Producing more stomach acid
4. Neutralizing excess stomach acid ✓
Which is commonly used in antacids?
1. HCl
2. H2SO4
3. Mg(OH)2 (magnesium hydroxide) ✓
4. NaCl
To neutralize acidic soil, farmers add:
1. Lime (CaCO3 or Ca(OH)2) ✓
2. Salt
3. More acid
4. Water only
A bee sting is acidic. What should you apply?
1. Lemon juice (acid)
2. Vinegar (acid)
3. Salt
4. Baking soda (base) ✓
What volume of 0.1 M NaOH is needed to neutralize 20 mL of 0.1 M HCl?
1. 20 mL ✓
2. 10 mL
3. 30 mL
4. 40 mL
In the equation: Acid + Base -> Salt + Water, what type of reaction is this?
1. Decomposition
2. Synthesis
3. Single replacement
4. Double replacement ✓
When HNO3 reacts with KOH, what salt is formed?
1. K2NO3
2. KNO3 ✓
3. KNO2
4. KN
Why should acid be added to water, not water to acid?
1. It is faster
2. It is safer - prevents violent boiling ✓
3. No reason
4. It makes weaker acid
What happens when you mix a strong acid with a strong base?
1. They neutralize forming salt and water ✓
2. They explode
3. Nothing
4. They form a stronger acid
The equivalence point in titration is when:
1. Acid and base exactly neutralize ✓
2. Indicator changes color
3. No more base is needed
4. pH is always 7
What is the purpose of wastewater neutralization?
1. Make it acidic
2. Remove all chemicals
3. Make it drinkable
4. Adjust pH to safe levels before discharge ✓
📖 science_quiz2_4_ph_indicators
What does pH measure?
1. Pressure
2. Temperature
3. Hydrogen ion concentration ✓
4. Volume
What is the pH range of the common pH scale?
1. 0 to 10
2. 0 to 14 ✓
3. 1 to 14
4. 0 to 7
What is the pH of a neutral solution at 25 degrees C?
1. 0
2. 7 ✓
3. 14
4. 10
Solutions with pH less than 7 are:
1. Neutral
2. Alkaline
3. Basic
4. Acidic ✓
Solutions with pH greater than 7 are:
1. Acidic
2. Neutral
3. Basic ✓
4. Neutral or acidic
If pH decreases by 1 unit, the H+ concentration:
1. Increases 10 times ✓
2. Decreases 10 times
3. Stays the same
4. Decreases 2 times
How many times more acidic is pH 2 compared to pH 4?
1. 100 times ✓
2. 10 times
3. 2 times
4. 4 times
What is the approximate pH of lemon juice?
1. 14
2. 2 ✓
3. 10
4. 7
What is the approximate pH of bleach?
1. 7
2. 0
3. 12 ✓
4. 2
What equation relates pH and pOH at 25 degrees C?
1. pH x pOH = 14
2. pH - pOH = 14
3. pH + pOH = 7
4. pH + pOH = 14 ✓
If pH is 3, what is pOH?
1. 7
2. 11 ✓
3. 14
4. 3
What are indicators?
1. Neutral compounds
2. Always colorless
3. Substances that change color at different pH ✓
4. Strong acids
What color does blue litmus paper turn in acid?
1. Red ✓
2. Yellow
3. Blue
4. Green
What color does red litmus paper turn in base?
1. Green
2. Yellow
3. Blue ✓
4. Red
What color is phenolphthalein in acidic solution?
1. Blue
2. Yellow
3. Pink
4. Colorless ✓
What color is phenolphthalein in basic solution?
1. Blue
2. Colorless
3. Pink ✓
4. Yellow
What color is methyl orange in acidic solution?
1. Red ✓
2. Yellow
3. Blue
4. Green
What is special about universal indicator?
1. It never changes color
2. It only works in acids
3. It is always red
4. It shows many different colors for different pH values ✓
What tool gives the most accurate pH measurement?
1. pH meter ✓
2. Phenolphthalein
3. Universal indicator
4. Litmus paper
What is the normal pH range of human blood?
1. 7.0 exactly
2. 8.0 - 8.5
3. 6.0 - 6.5
4. 7.35 - 7.45 ✓
What is the approximate pH of stomach acid?
1. 5.0 - 6.0
2. 1.5 - 3.5 ✓
3. 9.0 - 10.0
4. 7.0
Acid rain has a pH:
1. Greater than 7
2. Less than 5 ✓
3. Always 10
4. Equal to 7
What are buffers?
1. Solutions that resist pH changes ✓
2. Solutions that always have pH 7
3. Weak bases only
4. Strong acids only
The ideal pH range for swimming pools is:
1. 7.2 - 7.8 ✓
2. 4 - 5
3. 1 - 2
4. 12 - 14
What happens to pH as you dilute an acidic solution with water?
1. pH decreases
2. pH stays the same
3. pH becomes 14
4. pH increases toward 7 ✓
📖 science_quiz2_3_acids_and_bases
What ions do acids produce in water?
1. OH- ions
2. Na+ ions
3. H+ ions ✓
4. Cl- ions
What ions do bases produce in water?
1. H+ ions
2. OH- ions ✓
3. Na+ ions
4. CO2 ions
Which is a property of acids?
1. Bitter taste
2. Sour taste ✓
3. Slippery feel
4. pH greater than 7
Which is a property of bases?
1. Sour taste
2. pH less than 7
3. Turn red litmus red
4. Slippery/soapy feel ✓
What color does blue litmus paper turn in acid?
1. Blue
2. Green
3. Red ✓
4. Yellow
What color does red litmus paper turn in base?
1. Blue ✓
2. Red
3. Green
4. Yellow
What is the pH range for acids?
1. Less than 7 ✓
2. Equal to 7
3. Greater than 7
4. 7 to 14
What is the pH range for bases?
1. Less than 7
2. Greater than 7 ✓
3. 0 to 7
4. Equal to 7
Which is a strong acid?
1. Acetic acid
2. Carbonic acid
3. HCl (hydrochloric acid) ✓
4. Ammonia
Which formula represents sulfuric acid?
1. H2SO3
2. SO4
3. HSO4
4. H2SO4 ✓
Where do we find citric acid?
1. Batteries
2. Citrus fruits ✓
3. Drain cleaners
4. Cement
Which is found in vinegar?
1. Citric acid
2. Sulfuric acid
3. Acetic acid ✓
4. Nitric acid
What happens when zinc reacts with hydrochloric acid?
1. Produces hydrogen gas ✓
2. Produces oxygen gas
3. No reaction
4. Produces carbon dioxide
What gas is produced when acids react with carbonates?
1. Oxygen
2. Hydrogen
3. Carbon dioxide ✓
4. Nitrogen
Which is a common base found in cleaning products?
1. Citric acid
2. Lemon juice
3. Vinegar
4. Ammonia ✓
What is the formula for sodium hydroxide?
1. NaH
2. Na2O
3. NaOH ✓
4. NaCl
According to Arrhenius theory, what do acids produce in water?
1. H+ ions ✓
2. OH- ions
3. O2- ions
4. H2 gas
According to Arrhenius theory, what do bases produce in water?
1. H+ ions
2. H2 gas
3. O2- ions
4. OH- ions ✓
What is a proton donor in the Bronsted-Lowry theory?
1. An acid ✓
2. A base
3. A salt
4. Water
What is a proton acceptor in the Bronsted-Lowry theory?
1. An acid
2. Oxygen
3. A salt
4. A base ✓
Why should you add acid to water, not water to acid?
1. It is faster
2. Adding water to acid can cause violent boiling and splashing ✓
3. It is cheaper
4. It makes stronger acid
What color does phenolphthalein turn in a base?
1. Colorless
2. Pink ✓
3. Red
4. Yellow
Which acid is found in stomach acid?
1. Hydrochloric acid ✓
2. Acetic acid
3. Citric acid
4. Sulfuric acid
What is the purpose of antacids?
1. Neutralize excess stomach acid ✓
2. Increase stomach acid
3. Produce more enzymes
4. Kill bacteria only
Which property is characteristic of bases?
1. Sour taste
2. Turn blue litmus red
3. React with carbonates to produce CO2
4. Feel slippery ✓
📖 science_quiz2_2_types_of_reactions
What is the general pattern for a synthesis reaction?
1. A + BC -> AC + B
2. AB -> A + B
3. A + B -> AB ✓
4. AB + CD -> AD + CB
Which of the following is an example of a synthesis reaction?
1. 2H2O -> 2H2 + O2
2. 2Na + Cl2 -> 2NaCl ✓
3. Zn + 2HCl -> ZnCl2 + H2
4. AgNO3 + NaCl -> AgCl + NaNO3
What is the general pattern for a decomposition reaction?
1. A + B -> AB
2. AB -> A + B ✓
3. A + BC -> AC + B
4. Fuel + O2 -> CO2 + H2O
What often helps decomposition reactions occur?
1. Darkness
2. High pressure only
3. Low temperature
4. Heat, light, or electricity ✓
Which reaction type does 2HgO -> 2Hg + O2 represent?
1. Synthesis
2. Single replacement
3. Decomposition ✓
4. Combustion
What is the pattern for a single replacement reaction?
1. A + BC -> AC + B ✓
2. AB -> A + B
3. A + B -> AB
4. AB + CD -> AD + CB
In the reaction Zn + 2HCl -> ZnCl2 + H2, what type of reaction is this?
1. Single replacement ✓
2. Decomposition
3. Synthesis
4. Double replacement
What determines whether a single replacement reaction will occur?
1. Temperature only
2. The activity series ✓
3. pH level
4. Pressure
Which metal is most active according to the activity series?
1. Gold
2. Copper
3. Lithium ✓
4. Iron
What is the pattern for a double replacement reaction?
1. A + B -> AB
2. AB -> A + B
3. A + BC -> AC + B
4. AB + CD -> AD + CB ✓
Which of the following is a double replacement reaction?
1. C + O2 -> CO2
2. AgNO3 + NaCl -> AgCl + NaNO3 ✓
3. Mg + CuSO4 -> MgSO4 + Cu
4. 2H2O -> 2H2 + O2
What is a common driving force for double replacement reactions?
1. Formation of more reactants
2. Increase in temperature
3. Formation of a precipitate, gas, or water ✓
4. Decrease in volume
What type of reaction is combustion?
1. A special type with fuel + O2 ✓
2. Same as synthesis
3. Same as decomposition
4. Same as single replacement
What are the typical products of complete combustion of hydrocarbons?
1. CO and H2O
2. C and H2O
3. CO2 and H2O ✓
4. Only CO2
In the reaction CH4 + 2O2 -> CO2 + 2H2O, what type of reaction is this?
1. Synthesis
2. Decomposition
3. Single replacement
4. Combustion ✓
What happens during incomplete combustion?
1. More energy is released
2. Only water is produced
3. Carbon monoxide or carbon is produced ✓
4. No reaction occurs
How can you quickly identify a synthesis reaction?
1. Two or more reactants, one product ✓
2. Many reactants, many products
3. One reactant, many products
4. Always involves oxygen
Which reaction type is 2KClO3 -> 2KCl + 3O2?
1. Synthesis
2. Combustion
3. Single replacement
4. Decomposition ✓
In the activity series, can copper displace silver from a solution?
1. Yes, copper is more active ✓
2. No, copper is less active
3. Only at high temperature
4. Only in acidic solution
What type is the reaction: C + O2 -> CO2?
1. Double replacement
2. Decomposition
3. Single replacement
4. Synthesis ✓
When Mg reacts with HCl to produce MgCl2 and H2, what is replaced?
1. Mg
2. H ✓
3. Cl
4. Nothing
What indicates that AgNO3 + NaCl -> AgCl + NaNO3 is double replacement?
1. Only one product
2. Two compounds swap partners ✓
3. An element is free
4. Oxygen is involved
Why does the reaction 2Na + Cl2 -> 2NaCl release energy?
1. It is exothermic synthesis ✓
2. It requires heat
3. It is endothermic
4. It is combustion
Which is NOT a characteristic of combustion reactions?
1. Forms a precipitate ✓
2. Produces energy
3. Produces CO2 and H2O
4. Requires oxygen
In the reaction Pb(NO3)2 + 2KI -> PbI2 + 2KNO3, what forms as a precipitate?
1. KNO3
2. KI
3. Pb(NO3)2
4. PbI2 ✓
📖 science_quiz2_1_chemical_equations
What does a chemical equation represent?
1. A mathematical formula
2. A list of chemicals
3. A symbolic representation of a chemical reaction ✓
4. A recipe for cooking
In the equation 2H2 + O2 -> 2H2O, what are the reactants?
1. H2 only
2. H2 and O2 ✓
3. O2 only
4. H2O
What does the arrow (->) in a chemical equation indicate?
1. Subtraction
2. The direction of the reaction ✓
3. Addition
4. Multiplication
What is a coefficient in a chemical equation?
1. A superscript number
2. A subscript number
3. The atomic number
4. A number written in front of a formula ✓
What does the subscript "2" in H2 indicate?
1. Two grams
2. Two liters
3. Two atoms of hydrogen in one molecule ✓
4. Two molecules
Who formulated the law of conservation of mass?
1. Antoine Lavoisier ✓
2. Isaac Newton
3. Marie Curie
4. Albert Einstein
According to the law of conservation of mass, what must be equal in a chemical equation?
1. Total mass and number of each type of atom ✓
2. Number of molecules only
3. Volume of reactants and products
4. Temperature before and after
When balancing a chemical equation, what should you change?
1. Chemical symbols
2. Coefficients ✓
3. Arrows
4. Subscripts
In the balanced equation 2H2 + O2 -> 2H2O, how many hydrogen atoms are on the left side?
1. 8
2. 6
3. 4 ✓
4. 2
What does the state symbol (aq) represent?
1. Gas
2. Aqua
3. Solid
4. Aqueous (dissolved in water) ✓
Which state symbol represents a gas?
1. (l)
2. (g) ✓
3. (s)
4. (aq)
In a balanced chemical equation, the total number of each type of atom must be:
1. Greater on the reactant side
2. Greater on the product side
3. Equal on both sides ✓
4. Different on each side
What is the first step in balancing a chemical equation?
1. Write the unbalanced equation ✓
2. Change subscripts
3. Change the products
4. Add random coefficients
When balancing equations, which elements are typically balanced last?
1. Carbon
2. Metals
3. Hydrogen and oxygen ✓
4. Nitrogen
If an equation has 3 oxygen atoms on the left and 2 on the right, what should you do?
1. Leave it unbalanced
2. Change O2 to O3
3. Remove oxygen
4. Add coefficients to balance ✓
In the equation CH4 + 2O2 -> CO2 + 2H2O, how many oxygen atoms are on each side?
1. 8
2. 6
3. 4 ✓
4. 2
What does it mean when we say an equation is "balanced"?
1. It has equal numbers of each atom type on both sides ✓
2. It has an equal sign
3. It looks symmetrical
4. It has the same number of molecules
In the equation N2 + 3H2 -> 2NH3, how many hydrogen atoms are on the right side?
1. 2
2. 9
3. 3
4. 6 ✓
Why cannot you change subscripts when balancing equations?
1. It changes the identity of the substance ✓
2. It is against the rules
3. It makes the equation longer
4. It is too difficult
What is the smallest type of whole numbers you should use for coefficients?
1. Fractions
2. Any numbers
3. Decimal numbers
4. The smallest whole numbers possible ✓
In the photosynthesis equation, 6CO2 + 6H2O -> C6H12O6 + 6O2, how many carbon atoms are on the left?
1. 18
2. 6 ✓
3. 12
4. 1
What real-world application uses balanced chemical equations?
1. Only textbook problems and academic exercises
2. Many practical applications including engineering, industry, and medicine ✓
3. Sports statistics and game analysis
4. Artistic design and creative projects
Which of the following is a reactant in 2Na + Cl2 -> 2NaCl?
1. Na ✓
2. NaCl
3. Salt
4. Water
What does the coefficient "2" in 2H2O represent?
1. Two water molecules ✓
2. A subscript
3. Two hydrogen atoms
4. Two oxygen atoms
After balancing, if you have 4Fe + 3O2 -> 2Fe2O3, how many iron atoms are on each side?
1. 2
2. 8
3. 6
4. 4 ✓
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