1. KINETIC THEORY AND TEMPERATURE

2. Kinetic Theory Kinetic Theory: all particles of matter are in constant motion Kinetic energy: the energy that comes from an object’s motion. The more kinetic energy a particle has, the faster it moves.

3. Temperature The temperature of a substance is a measure of the average kinetic energy of its particles. The higher the temperature, the faster the particles move The SI unit for temperature is the Kelvin (K) K = °C + 273

4. Thermal Energy and heat In addition to having kinetic energy due to their movement, objects have potential energy Potential energy is energy due to the distance between two objects that are attracted to each other When you lift a weight high off the ground, it gains potential energy The sum of the kinetic and potential energies of all particles in an object is the thermal energy of the object Heat is the flow of thermal energy from something at high temperature to something at low temperature

5. Specific Heat The amount of thermal energy needed to raise the temperature of 1 kg of some material by 1 degree Celsius is called the specific heat In simpler terms, specific heat measures how easy or difficult it is to change the temperature of some material Water has a very high specific heat, so it takes a lot of energy to change the temperature of water We measure specific heat with a calorimeter

7. STATES (PHASES) OF MATTER

8. 3 Common states of matter on Earth Solid Definite shape and volume Liquid Definite volume but not shape Gas No definite shape or volume

9. Other state of matter: Plasma Plasma exists at extremely high temperatures Makes up 99% of the matter in the universe, but is nearly nonexistent on Earth

10. Why does matter exist in different phases? There are attractive intermolecular forces between all particles of matter The forces try to hold matter together in rigid formations (solid state) The only way some matter is able to remain liquid or gas is because of its kinetic energy, or speed

11. The battle between intermolecular forces and kinetic energy Intermolecular forces try to keep the particles together in tight, orderly formations The particles have kinetic energy, which tries to keep them moving around Whichever of these forces is stronger determines the state of matter state of matter

12. Phase changes

13. Heating curve for water

14. Phase changes Solid to liquid: melting (or fusion) Liquid to solid: freezing

15. Phase changes Liquid to gas: vaporization Below Boiling point = evaporation At boiling point = boiling

16. Phase changes Gas to liquid: condensation

17. Phase changes Solid to gas: sublimation

18. Phase changes Gas to solid: deposition

19. Vaporization: either boiling or evaporation When vaporization occurs at the boiling point, we call it boiling When vaporization occurs below the boiling point, it is evaporation Boiling occurs throughout a liquid Evaporation only occurs at the surface The boiling point of a liquid can be lowered by increasing the pressure of air pressing down on it

20. Phase Changes Temperature does not change during a phase change

21. Heating curve for water

22. Exothermic and endothermic phase changes Endothermic changes absorb heat In order for molecules to speed up and break formation, they must grab heat from their surroundings Exothermic changes release heat In order for molecules to slow down, they must dump heat into their surroundings

23. Exothermic or Endothermic phase change? Freezing………….. Melting……………. Vaporization……… Condensation……. Sublimation……… Deposition……….. Exothermic Endothermic Exothermic Endothermic Exothermic

24. Gas Laws

25. Pressure Pressure is the result of a force distributed over an area In a gas, pressure comes from collisions between particles and the wall of the container

26. Units of Pressure Newtons per square meter (N/m²) One N/m² is called a pascal (Pa) We often use kilopascals (kPa, 1kPa = 1000 Pa) Standard atmosphere (atm) 1 atm = 101,325 Pa or 101.325 kPa

27. Factors that affect gas pressure Number of particles Increasing the number of particles of gas will increase its pressure if volume and temperature are constant Temperature Increasing the temperature of a gas will increase its pressure if the number of particles and volume are constant Volume Decreasing the volume of a gas will increase its pressure if the number of particles and temperature are constant

28. Charles’ Law Jacques Charles, 1780 Published by Joseph Louis Gay- Lussac in 1802

29. Charles Law Note: Temperature must be in kelvin K = ºC + 273

30. Absolute Zero William Thomson “Lord Kelvin”

31. Boyle’s Law Robert Boyle, 1662

32. Boyle’s Law

33. The Combined Gas Law Note: Temperature must be in kelvin K = ºC + 273