Endothermic/exothermic reactions

Front

What are endothermic reactions?

Back

Reactions that absorb energy from their surroundings, usually in the form of heat.

Front

What are exothermic reactions?

Back

Reactions that release energy to their surroundings, usually in the form of heat.

Front

What does 'endo' mean in the context of chemical reactions?

Back

It means 'in' or 'absorbed'.

Front

What does 'exo' mean in the context of chemical reactions?

Back

It means 'out' or 'released'.

Front

Give an example of an endothermic reaction.

Back

Photosynthesis: @@6 ext{CO}_2 + 6 ext{H}_2 ext{O} + ext{Energy} ightarrow ext{C}_6 ext{H}_{12} ext{O}_6 + 6 ext{O}_2@@.

Front

Give an example of an exothermic reaction.

Back

Combustion of hydrogen: @@ ext{O}_2(g) + 2 ext{H}_2(g) ightarrow 2 ext{H}_2 ext{O}(g) + ext{Energy}@@.

Front

What is the energy change in an exothermic reaction?

Back

Energy is released to the surroundings.

Front

What is the energy change in an endothermic reaction?

Back

Energy is absorbed from the surroundings.

Front

How can you identify an exothermic reaction?

Back

It usually feels hot to the touch and may produce light or sound.

Front

How can you identify an endothermic reaction?

Back

It usually feels cold to the touch and requires heat to proceed.