Chapter 9, Problem 8RQ

Distinguish between a joule and acalorie.

To determine

The difference between a joule and a calorie.

Answer to Problem 8RQ

A calorie is the amount of heat needed to change the temperature of one gram of water by one degree Celsius. While it takes $4.18$ joules of heat to change $1$ gram of water by $1$ Celsius degree.

Explanation of Solution

Joule	Calorie
Joule is the commonly used unit for measuring the heat.	Calorie is the commonly used unit for measuring the heat in the United States.
It takes $4.18$ joules of heat to change $1$ gram of water by $1$ Celsius degree	A calorie is defined as the amount of heat needed to change the temperature of $1$ gram of water by $1$ Celsius degree.

The relationship between the calories and joules is that $1\text{calorie}=4.18\text{joules}$.

Conclusion:

Therefore, a calorie is the amount of heat needed to change the temperature of one gram of water by one degree Celsius. While it takes $4.18$ joules of heat to change $1$ gram of water by $1$ Celsius degree.