Question

Which of the following measurements is used to measure the enthalpy of combustion? A. None of these B. Measuring the change in temperature when two liquids are mixed. C. It cannot be measured, only calculated using the equation: q = mc∆T. D. Measuring the change in temperature of a beaker of water.

Answer 1

Answer: Option (C) is the correct answer.

Explanation:

In a substance, the total energy of its molecular motion is known as heat. Whereas when we measure the average energy of molecular motion of a substance then it is known as temperature.

So, any increase or decrease in temperature will lead to change in heat of a substance.

When one mole of a substance is burned then the amount of energy released  in the form of heat is known as heat of combustion.

Relation between heat and temperature is as follows.

                    q = $m \times C \times \Delta T$

Thus, we can conclude that to measure the enthalpy of combustion it cannot be measured, only calculated using the equation; q = $mc \Delta T$.