conversion of energy

What does conservation of energy mean in a chemical reaction?

Energy cannot be created or destroyed — it is only transferred. The total amount of energy stays the same.

What happens to the energy of the products when a reaction transfers energy to the surroundings?

The products have less energy than the reactants because energy has been transferred to the surroundings.

What is an exothermic reaction? Give some examples.

An exothermic reaction transfers energy to the surroundings, so the temperature increases. (combustion, oxidation and neutralisation.)

What are two everyday uses of exothermic reactions?

Self-heating cans and hand warmers.

What is an endothermic reaction? Give some examples.

An endothermic reaction takes in energy from the surroundings, so the temperature decreases. (thermal decomposition and citric acid + sodium hydrogencarbonate.)

What is an everyday use of endothermic reactions?

Sports injury cold packs, because the reaction takes in energy from the surroundings, making them cold.