Inference Questions

15th Question

Calorimetry

One technique we can use to measure the amount of heat involved in a chemical or physical process is known as calorimetry. Calorimetry is used to measure amounts of heat transferred to or from a substance. To do so, the heat is exchanged with a calibrated object (calorimeter). The temperature change measured by the calorimeter is used to derive the amount of heat transferred by the process under study. The measurement of heat transfer using this approach requires the definition of a system (the substance or substances undergoing the chemical or physical change) and its surroundings (the other components of the measurement apparatus that serve to either provide heat to the system or absorb heat from the system). Knowledge of the heat capacity of the surroundings, and careful measurements of the masses of the system and surroundings and their temperatures before and after the process allows one to calculate the heat transferred.

A calorimeter is a device used to measure the amount of heat involved in a chemical or physical process. For example, when an exothermic reaction occurs in solution in a calorimeter, the heat produced by the reaction is absorbed by the solution, which increases its temperature. When an endothermic reaction occurs, the heat required is absorbed from the thermal energy of the solution, which decreases its temperature. The temperature change, along with the specific heat and mass of the solution, can then be used to calculate the amount of heat involved in either case.

Q. Paragraph 1 suggests that calorimetry …

• a. Calorimetry measures the heat of all objects

• b. It can only be used to measure the amount of heat in a chemical process

• c. There is more than one way to measure the amount of heat in a chemical or physical process

• d. The heat is exchanged with a calorimeter

C is correct because paragraph 1 begins with “one technique we can use to measure the amount of heat”, and also says, “using this approach”, both of which indicate that this method of measuring is not the only one. Even though the passage states "the heat is exchanged with a calibrated object (calorimeter), D is still incorrect because this is an inference question, not a detail question.