1. Ch. 16 Sec. 1 Thermal Energy and Matter

2. Work and Heat In a drill, the drill does work on the screw –Energy is lost to the screw (friction) Heat is the transfer of thermal energy Heat flows spontaneously from hot to cold objects

3. Temperature “How hot or cold something is” Meas. of avg. K.E. of the particles in the object. Scales ~ Celsius (°C) 0° - 100° ~ Fahrenheit (°F) 32° - 212° ~ Kelvin (K) 0 K – Absolute zero

4. Thermal Energy Depends on mass, temperature, and phase Grand total energy Which beaker has more thermal energy? Why?

5. Thermal Energy Contraction –Slower particles collide less often –Less force exerted –Gases pressure decreases

6. Thermal Energy Expansion –Increase in the volume of a material –Gases particles move further apart

7. Ability of a sub. to absorb heat energy. The amount of heat needed to raise the temp. of 1 g of the material 1 °C. Units: J/g-°C. Specific Heat Specific Heat of Materials SubstanceSpecific Heat (J/g-°C) Water4.18 Wood1.76 Aluminum.90 Glass.66 Iron.45 Copper.38 Silver.24

8. The thermal energy changes when heat flows into or out of objects. Q = mc∆t –Q = thermal energy (J) –M = mass (g) –C = specific heat (J/g-°C) –∆t = change in temp. (°C) Changes in Thermal Energy

9. Calculate Thermal Energy How much thermal energy is needed to raise the temperature of 400g of water from 21 °C to 100 °C? Q = mc∆t Q = 400g · 4.18 J/g-C · 79 ° C Q = 132,088 J