Physical Science, Unit 2, Lesson 3
Exam Question & Answers 2025
What happens in every chemical reaction? - CORRECT
ANSWERS ✔✔The release or absorption of energy
something that moves or changes matter - CORRECT
ANSWERS ✔✔Energy
energy that is stored by the arrangement of atoms -
CORRECT ANSWERS ✔✔chemical energy
main source of energy for vehicles and electricity
generation - CORRECT ANSWERS ✔✔Energy released
during the combustion of fossil fuels
combustion - CORRECT ANSWERS ✔✔oxygen reacts
with a substance and releases a large amount of energy
in the form of heat and light
Why did the candles stop burning when the students
placed glass jars over them? - CORRECT ANSWERS
✔✔The jars prevent oxygen in the surrounding air from
reaching the flames, so the flames go out.
Which candle burned the longest time? Why? - CORRECT
ANSWERS ✔✔Candle in the biggest jar burned the
, Physical Science, Unit 2, Lesson 3
Exam Question & Answers 2025
longest time. It's because it received more oxygen than
the other two candles.
What visual evidence shows that combustion reactions
release energy? - CORRECT ANSWERS ✔✔The flames
indicate that combustion reactions release energy.
Which two kinds of energy are associated with flames? -
CORRECT ANSWERS ✔✔Light and thermal (heat)
energy
Why do iron filings burn while a heavy iron pipe does not?
Why do twigs ignite better than logs? Give your answer in
terms of atoms. - CORRECT ANSWERS ✔✔When the
reactions take place, the atoms of reactants rearrange to
form products. The particles of the reactants must collide
or come into contact with each other. Using smaller
pieces of the solids (powders, bits, flecks) increases the
area of contact between atoms.
endothermic reactions. - CORRECT ANSWERS
✔✔chemical reactions that absorb energy from it's
surroundings.
Exam Question & Answers 2025
What happens in every chemical reaction? - CORRECT
ANSWERS ✔✔The release or absorption of energy
something that moves or changes matter - CORRECT
ANSWERS ✔✔Energy
energy that is stored by the arrangement of atoms -
CORRECT ANSWERS ✔✔chemical energy
main source of energy for vehicles and electricity
generation - CORRECT ANSWERS ✔✔Energy released
during the combustion of fossil fuels
combustion - CORRECT ANSWERS ✔✔oxygen reacts
with a substance and releases a large amount of energy
in the form of heat and light
Why did the candles stop burning when the students
placed glass jars over them? - CORRECT ANSWERS
✔✔The jars prevent oxygen in the surrounding air from
reaching the flames, so the flames go out.
Which candle burned the longest time? Why? - CORRECT
ANSWERS ✔✔Candle in the biggest jar burned the
, Physical Science, Unit 2, Lesson 3
Exam Question & Answers 2025
longest time. It's because it received more oxygen than
the other two candles.
What visual evidence shows that combustion reactions
release energy? - CORRECT ANSWERS ✔✔The flames
indicate that combustion reactions release energy.
Which two kinds of energy are associated with flames? -
CORRECT ANSWERS ✔✔Light and thermal (heat)
energy
Why do iron filings burn while a heavy iron pipe does not?
Why do twigs ignite better than logs? Give your answer in
terms of atoms. - CORRECT ANSWERS ✔✔When the
reactions take place, the atoms of reactants rearrange to
form products. The particles of the reactants must collide
or come into contact with each other. Using smaller
pieces of the solids (powders, bits, flecks) increases the
area of contact between atoms.
endothermic reactions. - CORRECT ANSWERS
✔✔chemical reactions that absorb energy from it's
surroundings.
