1. Chapter 12.1

2. 1. Everything is made of particles 2. These particles move 3. Hot things move faster than cold things

3.  Temperature – a measure of average kinetic energy of an object  Thermometer - device that measures temperature (and, as a result, average KE)

4.  Always from hot to cold objects

5.  Heat flow stops only when all objects are in equilibrium (at the same temp)

6.  If A is 75 degrees and B is 25 degrees, at which temperature are they both in equilibrium?  To solve, first add up the different temperatures  Next, divide the total temp by 2 (because we have 2 objects)  This is the equilibrium temperature  Answer = 50 degrees

7.  The temp at which molecular motion stops  Is this cold or hot??

8.  Know how to do these…  50°C = _______ K  325 K = ________°C

10.  Energy transfer when objects are in direct contact. There must be matter in order for energy to transfer by conduction.

11.  Energy transfer by air or water currents.  Objects are not in direct contact  Look for currents  Know that hot air and water rises!!  Matter is required for heat transfer by convection

12.  Energy transfer thru empty space  No matter is required!!  Its how the sun heats the Earth  Sunbathers are often used as examples of heating by radiation

16. Q = Cm Δ T Q = heat gained or lost (J) m = mass in kg C = specific heat (see p.279) Δ T = temp change (K or °C)

17. T f = m a C a T ai +m b C b T bi m a C a +m b C b

18. How much heat is needed to raise the temperature 1.5 kg of water from 22°C to 35°C? m = 1.5 kg Δ T = 15°C C = ?? What is changing temperature? Use the specific heat for whatever is changing temp (see page 279)

19. Q = 4180 x 1.5 x 15 Q = 94,050 J

20. A 5.0 kg sample of water at 25°C is mixed with 1.5 kg of water at 75°C. What is the final temperature of the mixture? Use the Tf formula…

21.  Tf = 5 x 4180 x 25+1.5 x 4180 x 75 5 x 4180+1.5 x 4180 Tf = 459800+470250 20900+6270 Tf = 34°C

22. Page 296 #’s 23 – 24 and 27-28