Energy Changes

Question 1

What is an exothermic reaction?

Answer 1

An exothermic reaction is one that releases energy to the surroundings, usually in the form of heat

Question 2

Example of an exothermic reaction?

Answer 2

• Combustion
• Respiration
• Hand warmers

Question 3

What is an endothermic reaction?

Answer 3

Absorbs energy from the surroundings, usually in the form of heat.

Question 4

Example of an endothermic reaction?

Answer 4

• Photosynthesis
• Evaporation
• Alkane cracking

Question 5

What is a reaction profile?

Answer 5

Shows how the energy of reactants and products changes as a chemical reaction progresses

Question 6

How is the energy of products and reactants shown in an exothermic reaction profile?

Answer 6

In an exothermic reaction, the products are shown lower on the reaction profile compared to the reactants because the products have less energy

Question 7

What is activation energy?

Answer 7

Activation energy is the minimum amount of energy required for the reactant particles to collide with enough energy to react

Question 8

How is activation energy shown on a reaction profile?

Answer 8

Activation energy is shown as the difference in energy between the reactants’ energy level and the highest point on the reaction profile curve

Question 9

How does a reaction profile change if the activation energy is higher?

Answer 9

If the activation energy is higher, the curve on the reaction profile will be higher

Question 10

How does a reaction profile change if the activation energy is lower?

Answer 10

If the activation energy is lower, the curve on the reaction profile will be lower

Question 11

What does the area between the reactants and products represent in an exothermic reaction?

Answer 11

Represents the energy released to the surroundings

Question 12

How are the reactants and products positioned on an endothermic reaction profile?

Answer 12

In an endothermic reaction, the products are positioned higher than the reactants, indicating they have more energy.

Question 13

What type of energy exchange occurs in exothermic reactions?

Answer 13

In exothermic reactions, energy is released as heat to the surroundings.

Question 14

What happens when energy is transferred to the surroundings in a reaction?

Answer 14

When energy is transferred to the surroundings, the temperature of the surroundings increases