# Summarizing Heat

## Summary

• Heat and work are the two distinct methods of energy transfer.
• Heat is energy transferred solely due to a temperature difference.
• Any energy unit can be used for heat transfer, and the most common are kilocalorie (kcal) and joule (J).
• Kilocalorie is defined to be the energy needed to change the temperature of 1.00 kg of water between $$\text{14}\text{.5ºC}$$ and $$\text{15}\text{.5ºC}$$.
• The mechanical equivalent of this heat transfer is $$1\text{.00 kcal}\phantom{\rule{0.25em}{0ex}}=\phantom{\rule{0.25em}{0ex}}\text{4186 J.}$$

## Glossary

### heat

the spontaneous transfer of energy due to a temperature difference

### kilocalorie

$$\phantom{\rule{0.25em}{0ex}}1\phantom{\rule{0.25em}{0ex}}\text{kilocalorie}\phantom{\rule{0.25em}{0ex}}\text{=}\phantom{\rule{0.25em}{0ex}}\text{1000}\phantom{\rule{0.25em}{0ex}}\text{calories}$$

### mechanical equivalent of heat

the work needed to produce the same effects as heat transfer