Question

How can a calorimeter measure energy?

Answer 1

The calorimeter traps all the heat from a chemical reaction, we measure the effect of that heat on the temperature of water in the calorimeter, and we can then calculate the heat energy released by the reaction.

The calorimeter is an insulated container, in which we place a measured mass of water. We know that for every `1.00^(o)`C temperature rise, each gram of water in the calorimeter absorbs 1 calorie (or 4.184J) of heat energy.

Suppose the calorimeter contains 100.0 g of water, and a reaction occurs that causes the temperature of the water to increase #1.50^(o)C as a result of a chemical reaction. Then the water absorbs 150. calories

(100.0 g x `1.50^(o)`C x 1 calorie/`g^(o)`C)

or 628J of heat energy as a result of the reaction. We can then relate this energy to the number of grams of the particular substance used in the reaction.