Exothermic and Endothermic Reactions

C5 - Energy Changes

What is a key characteristic of exothermic reactions regarding energy transfer?

Exothermic reactions transfer energy from the reacting molecules to the surroundings, increasing the temperature of the surroundings.

What happens to the temperature of the surroundings during an exothermic reaction?

The temperature of the surroundings increases.

What is one example of an exothermic reaction?

Combustion (burning) is an example of an exothermic reaction.

What do energy profile diagrams represent in chemical reactions?

They represent the energy changes that take place during the reactions.

In an exothermic reaction, how does the energy of the products compare to the energy of the reactants?

The products have less energy than the reactants.

What is the name of the energy that is gained or lost in a reaction?

The difference in energy between the reactants and products indicates the energy released or absorbed.

Name two practical uses of exothermic reactions.

Exothermic reactions are used in hand warmers and self-heating cans.

What defines an endothermic reaction in terms of energy?

Endothermic reactions take in energy from their surroundings, causing a decrease in the temperature of the surroundings.

What is a good example of an endothermic reaction?

Thermal decomposition is a good example of an endothermic reaction.

What is activation energy?

Activation energy is the minimum amount of energy that particles must have in order to react.

How is the activation energy represented on an energy profile diagram?

The activation energy is represented as the energy from the reactants to the peak of the curve.

What common feature do both exothermic and endothermic reactions share in their energy profiles?

Both types of reactions show a rise to a peak called activation energy.