1. Define your system (the substance(s) that are changing).

2. Write down unknown information (i.e. what you are looking for).

3. Write down what you know. Remember if you are given heat value (in cal or J) you need to determine the sign of this value:

- If system is losing heat (giving to surrounding), the heat sign is
**negative** - If system is gaining heat (absorbing from surrounding), the heat sign is
**positive** - If you are calculating the heat value, you don't determine the sign your calculations will

- Phase change (called
**Latent heat**) heat equation: - Non-phase change (called
**Sensible heat**) heat equation: - You mst show deltaH = T
_{final}- T_{initial}and resulting value & sign

5. Plug the numbers you are given into the formula (show work if you need to convert units into other units. (e.g. grams into kilograms)

6. Do math. (make sure to have units on all numbers and keep appropriate sig fig and scientific notation).

7. Check answer including correct number of sig figs, scientific notation, and proper units! Remember that the last calculation step determines the method of determining sig figs.