Author Question: Substance A has twice the heat capacity of substance B. If equal masses of both substances are ... (Read 75 times)

melina_rosy · **on:** Jul 28, 2018

Substance A has twice the heat capacity of substance B. If equal masses of both substances are raised 10 C and substance A gains 30 kJ of energy, substance B gains 15 kJ of energy.

What will be an ideal response?

Question 2

All forms of energy are equivalent in terms of doing useful work.

What will be an ideal response?

flexer1n1 · **Reply #1 on:** Jul 28, 2018

Answer to Question 1

The amount of heat transferred is DQ = (heat capacity)DT. Given that the
temperatures rise the same amount, the substance with the greater heat capacity will transfer
the greater amount of heat. Therefore, the statement is correct.

Answer to Question 2

This is not true. We have seen that the quality of the energy is not the same.
Electrical energy can all be converted to useful work, but thermal energy cannot. We have
seen that thermal engines operate between temperature reservoirs and that thermal energy is
taken from the high temperature reservoir, work is done, and thermal energy is exhausted to
the low temperature reservoir. The energy rejected to the low temperature reservoir cannot
be used to do work.