Which instrument is used to measure the amount of heat exchanged in a system?

• A. Calorimeter
• B. Barometer
• C. Thermometer
• D. Hygrometer

Answer: (A)

Measuring how much heat is exchanged is done with a calorimeter. It’s built to capture the energy transfer as heat and relate it to a temperature change in the system and its surroundings. By knowing the calorimeter’s heat capacity (or the system’s mass and specific heat), you can calculate the heat exchanged from the observed temperature change using Q = CΔT or Q = m c ΔT. Different types exist, like bomb calorimeters for constant-volume reactions or coffee-cup calorimeters for constant-pressure setups, but the essential idea is that the temperature change inside the calorimeter is a direct clue to how much heat moved.

The other instruments measure different things: a barometer gauges atmospheric pressure, a thermometer reads temperature, and a hygrometer checks humidity. They don’t provide a direct measure of heat transfer.