Energy — Test Answers

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1
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Which statement best describes heat and thermal energy?

A
They are different words for the same thing.
B
They represent different concepts.
C
Heat is what happens when thermal energy stops moving between substances.
D
Thermal energy is what happens when heat moves between substances.
2
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Which of these actions would increase heat transfer between two objects?

e
establishing their thermal equilibrium
i
increasing the area of their contact
u
using objects with similar specific heats
r
reducing the time of their contact
4

Which statement describes mechanical energy?

A
the energy that is stored in chemical bonds
B
the energy that is associated with temperature
C
the sum of the kinetic energy and the potential energy of an object
D
the type of energy that is associated with electromagnetic radiation
5

A book is falling from the top shelf of a bookcase. Which statement correctly describes the change in the energy of the book?

A
The potential energy and kinetic energy remain the same.
B
The potential energy decreases as kinetic energy increases.
C
The kinetic energy decreases as potential energy increases.
D
The kinetic energy remains at zero, but potential energy increases.
6

Which statement describes the law of conservation of energy?

A
All systems will exchange matter and energy with their surroundings.
B
All systems can exchange energy, but not matter, with their surroundings.
C
Energy cannot be created nor destroyed, but it changes from one form to another.
D
Energy is destroyed in most chemical reactions when new products are formed.
7

Reactant P contains 50 J of energy, and reactant Q contains 35.3 J of energy. The reactants combine to form product PQ, which contains 104 J of energy. What is the energy transformation?

A
Energy is absorbed because the product has more energy than the reactants have.
B
Energy is absorbed because the product has less energy than the reactants have.
C
Energy is lost because the product has more energy than the reactants have.
D
Energy is lost because the product has less energy than the reactants have.
8

How does an increase in reactant concentration affect the rate of reaction?

A
It leads to more frequent collisions, which increase reaction rate.
B
It leads to less frequent collisions, which increase reaction rate.
C
It leads to more frequent collisions, which decrease reaction rate.
D
It leads to less frequent collisions, which decrease reaction rate.
9

Which statement is usually true about the relationship between activation energy and reaction rates?

A
Low activation energy barriers result in low rates.
B
High activation energy barriers result in low rates.
C
Low activation energy barriers result in no reaction.
D
High activation energy barriers result in no reaction.
11

Which is true about reaction rates?

A
High reaction rates occur only in spontaneous reactions.
B
Low reaction rates occur only in nonspontaneous reactions.
C
Reaction rates are not dependent on high or low activation energies.
D
Reaction rates are not related to spontaneity.

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