1 / 18

Warm-up

Warm-up. What are the Laws of Thermodynamics? What is heat?. Objectives I. Discuss assumptions of atomic theory. Discuss temperature and thermal equilibrium. Calculate thermal expansion. Discuss anomalous behavior of water. Apply gas laws. Apply kinetic theory to define temperature.

kennan-fowler
Download Presentation

Warm-up

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Warm-up • What are the Laws of Thermodynamics? • What is heat?

  2. Objectives I • Discuss assumptions of atomic theory. • Discuss temperature and thermal equilibrium. • Calculate thermal expansion. • Discuss anomalous behavior of water. • Apply gas laws. • Apply kinetic theory to define temperature.

  3. Objectives II • Define heat, internal energy, and temperature. • Define and apply specific heat principles to solve calorimetry problems. • Discuss latent heat and apply to solve problems. • Discuss heat transfer processes.

  4. Temperature • Measure of how hot or cold an object is. • Physical properties • Expansion and contraction • Electrical resistance • Color • Thermometers • Temperature scales • Absolute zero

  5. Gas Laws • Boyles Law: V1/P (absolute pressure) • Charles’s Law: V  T • Gay-Lussac’s Law: P T

  6. Ideal Gas Law • Ideal Gas Law: PV=nRT where R=universal gas constant (8.315 J/(mol-K)) • PV = NkT where k=Boltzmann’s constant = R/NA = 1.38 x 10-23 J/K and N = number of molecules of gas in the sample.

  7. practice • How many moles of an ideal monatomic gas are in a fixed container of size .5m3 at 2.0x105 N/m2 and 10°C?

  8. practice • An ideal gas filled sphere of volume .05m3 inflates to .7m3 when heated from 20°C to 30°C. If the final pressure is 2.05x105 N/m2, what was the initial pressure?

  9. Temperature of Gasses • Avg translational KE of molecules in a gas is directly proportional to absolute temperature • KEavg = ½ mv2 = 3/2 kBT • vavg = vrms =

  10. Practice • What is the average translational kinetic energy of molecules in a gas at 37°C?

  11. practice • What is the rms speed of air molecules O2 and N2 at room temperature (20°C) if the atomic mass of O is 16 amu, and the atomic mass of N is 14amu?

  12. Thermal Equilibrium • Heat energy flows to establish equilibrium. • Use of thermometers to verify thermal equilibrium of two systems.

  13. Thermal Expansion • Most substances expand with increase in temperature. • Amount varies with material.  L=L0T V =V0T

  14. Practice • An aluminum block is 51.25m long at 20.0°C. If the coefficient for linear expansion of aluminum is 25.0x10-6/C°, what is it’s length at 0°C.

  15. Water • From 0° to 4°C, water contracts to reach densest form. Then, water expands with temperature increases. • Solid water (ice) is less dense than liquid. • Icy ponds

  16. Heat • Transfer of thermal energy due to temperature differences. • James Joule and Mechanical equivalent of heat: 4.186 J = 1 cal • 1 cal is heat required to raise temperature of 1 g of water from 14.5 to 15.5°C.

  17. Specific Heat • c=Q/(m T) where c=specific heat; Q=heat; m=mass; and T is temperature. • c is property of material. • cv and cp for gases

  18. Practice: • Work on HW 10; you may ask quick questions about HW 9

More Related