1 / 13

Temperature and Kinetic Theory

Temperature and Kinetic Theory. Atomic Theory. Atom – smallest piece of mater Atomic Mass  unit – atomic mass unit – amu  1amu = 1.66 x 10 -27 kg Molecular Mass - sum of all masses in molecules Brownian motion – atoms are in continuous motion. Examples.

mili
Download Presentation

Temperature and Kinetic Theory

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. Temperature and Kinetic Theory

  2. Atomic Theory • Atom – smallest piece of mater • Atomic Mass  unit – atomic mass unit – amu  1amu = 1.66 x 10-27 kg • Molecular Mass - sum of all masses in molecules • Brownian motion – atoms are in continuous motion

  3. Examples • What is the atomic mass of He in amu? What is this mass in kg? • What is the molecular mass of Fe2O3 in amu? What is this mass in kg?

  4. Properties • Atoms and molecules exert attractive and repulsive forces on each other • Solids – attractive forces are strong enough to hold the particles in fixed positions • Liquids – move faster, forces are weaker, particles roll over one another • Gases – forces very weak, particles do not stay together

  5. Temperature • Measure of average kinetic energy (speed) – higher temperature means particles are on average moving faster • Many properties change with temperature: size, electrical resistance, color of light emitted • Thermometer – instrument that measures temperature (relies on expansion of materials)

  6. Temperature Scale • Celsius C = 5/9 (F – 32) F = 9/5C + 32 • Kelvin – scientific scale K = C + 273.15 O K – absolute zero – all atomic motion stops

  7. Thermal Equilbrium • When two objects of different temperature are placed in contact, they will eventually reach the same temperature • Heat flows from high temp. to low temp. • Zeroth Law of Thermodynamics – if two systems are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other

  8. Thermal Expansion • Expansion of a material due to an increase in temperature • Amount a substance expands or contracts depends on the material • The amount the length changes is directly proportional to the amount the temp changes and the original length

  9. Expansion Equations - Solids L = LoT  - coefficient of linear expansion which depends on the material (pg.344) A = 2AoT V = 3VoT

  10. Example • A steel bed of a suspension bridge is 200m long at 20°C. If the extreme temperatures are -30°C and 40°C, how much will it contract or expand?

  11. Example • An iron ring is to fit snug on a cylindrical iron rod. At 20°C, the diameter of the rod is 6.445cm and diameter of the ring is 6.420cm. To slip over, the ring must be slightly larger than the rod by about .008cm. To what temperature must the ring be heated?

  12. Volume Expansion - Liquid • Volume change of the liquid can be related by a similar equation V = VoT -coefficient of volume expansion

  13. Example • A 70L steel gas tank is filled at 20°C. The car is left to sit in the sun and the tank reaches 40°C. How much gas would overflow from the tank (if any)?

More Related