1. Thermochemistry Study of heat in chemical reactions. Heat will travel between a system and its surroundings Heat is measured in Joules (J) Metric  English: BTU (British Thermal Unit) 1 BTU = 1.06 kJ

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3. Calculating Heat The heat that transfers between substances can be calculated with the following equation: q = (s) (m) (∆T)

4. Calculating Heat q : amount of heat (energy) transferred s: specific heat m: mass (use density to change from mL to g!) ∆T: change in temperature

5. Calculating Heat Specific Heat is the quantity of heat needed to raise one gram of a substance 1.0 ⁰C. Each specific substance has its own specific heat. (pg. 394)

6. [http://wps.prenhall.com/wps/media/objects/602/616516/Media_Assets/Chapter08/Text_Images/FG08_TB01.JPG] Round to 4.18

7. Calculating Heat Example: How much heat is needed to warm a 200.0 mL cup of coffee (H 2 O) from 20.0 ⁰C to 75.0 ⁰C?

8. Calculating Heat 45980 J, but only 3 significant digits so…. 4.60 x 10 4 J or 46.0 kJ

9. Calculating Heat What is the specific heat of lead? 100.0 °C 20.0 °C 28.8 °C

10. 1 st Step - Calculate “q” for the H 2 O q = 1840 J 20.0 °C

11. 2 nd Step - Calculate “s” for Lead 100.0 °C q = (150.0 g)(s)(71.2 o C) 1840 J Energy that water absorbed in step one was supplied by the metal! s = 0.172 J/(g x C) for Lead