Question 1

Which of the following best describes an endothermic reaction?

Accepted Answer

A reaction that absorbs heat from the surroundings.

Question 2

During an endothermic reaction, what happens to the temperature of the surroundings?

Accepted Answer

It decreases.

Question 3

Which of the following processes is an example of an endothermic reaction?

Accepted Answer

Water boiling.

Question 4

In an exothermic reaction, energy is transferred in which direction?

Accepted Answer

From the system to the surroundings.

Question 5

Which of the following is a real-world example of an exothermic reaction?

Accepted Answer

CO$$_2$$ burning.

Question 6

What happens to the bonds in molecules during an endothermic reaction?

Accepted Answer

Bonds are broken.

Question 7

Which graph best represents the energy change in an exothermic reaction?

Accepted Answer

Energy of products is lower than reactants.

Question 8

A student touches a beaker in which an exothermic reaction is occurring. What sensation will they most likely feel?

Accepted Answer

The beaker feels hot.

Question 9

Which of the following statements is true about endothermic reactions?

Accepted Answer

They absorb energy from the surroundings.

Question 10

If a chemical reaction causes the temperature of the surroundings to decrease, what type of reaction is it?

Accepted Answer

Endothermic.

Question 11

Which process involves the absorption of heat and a phase change from liquid to gas?

Accepted Answer

Boiling.

Question 12

A reaction in a cold pack is an example of which type of reaction?

Accepted Answer

Endothermic.

Question 13

Which of the following is NOT a characteristic of exothermic reactions?

Accepted Answer

Absorb heat from the surroundings.

Question 14

What is the sign of the enthalpy change ($$\Delta H) $$for an endothermic reaction?

Accepted Answer

$$\Delta H is $$positive.

Question 15

Which of the following best explains why water boiling is an endothermic process?

Accepted Answer

Heat is absorbed to break intermolecular bonds.

Question 16

During which process does a substance absorb energy and change directly from solid to gas?

Accepted Answer

Sublimation.

Question 17

Which of the following reactions would you expect to feel cold to the touch?

Accepted Answer

Reaction in a cold pack.

Question 18

If the energy of the products is lower than the energy of the reactants, what type of reaction has occurred?

Accepted Answer

Exothermic.

Question 19

Which of the following is a correct representation of the energy profile for an endothermic reaction?

Accepted Answer

Products have higher energy than reactants.

Question 20

A student places a chemical in water and notices the temperature drops. What can be concluded about the reaction?

Accepted Answer

It is endothermic.

Endothermic and Exothermic Reactions: Key Concepts and Examples

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