1. Kinetic Theory & Gas Laws

2. Kinetic-Molecular Theory – explains how particles in matter behave 1. All matter is composed of small particles that are far apart. Gas is mostly empty space 2. Particles are in constant, random motion. 3. Particles collide with each other and walls of their containers: collisions create pressure Kinetic-Molecular Theory – explains how particles in matter behave 1. All matter is composed of small particles that are far apart. Gas is mostly empty space 2. Particles are in constant, random motion. 3. Particles collide with each other and walls of their containers: collisions create pressure 4. Collisions are elastic = no KE lost 4. Collisions are elastic = no KE lost 5. No attractive/repulsive forces between particles 5. No attractive/repulsive forces between particles

4. Thermal energy – total energy of a material’s particles; causes particles to vibrate in place Thermal energy – total energy of a material’s particles; causes particles to vibrate in place Average kinetic energy – temperature of the substance, or how fast the particles are moving Average kinetic energy – temperature of the substance, or how fast the particles are moving

5. States of Matter – solid, liquid, gas State of Matter depends on: 1.Average Kinetic Energy (or Temperature) 2.The attractive forces between and within the particles a.Intermolecular b.Intramolecular

6. Solid state – particles are closely packed together in a specific type of geometric arrangement: least KE, strong attractive forces. Solid state – particles are closely packed together in a specific type of geometric arrangement: least KE, strong attractive forces.

7. Liquid state – a solid begins to liquefy at the melting point as the particles gain enough energy to overcome the attractive forces between the particles Liquid state – a solid begins to liquefy at the melting point as the particles gain enough energy to overcome the attractive forces between the particles The stronger the attractive forces, the greater energy required to break bonds between particles

8. Gaseous state – a liquid’s particles have enough energy to escape the attractive forces of the other particles in the liquid highest KE level. Gaseous state – a liquid’s particles have enough energy to escape the attractive forces of the other particles in the liquid highest KE level. Gas particles spread evenly throughout their container in the process of diffusion. Depends on the mass of the particles. Small mass moves faster. Gas particles spread evenly throughout their container in the process of diffusion. Depends on the mass of the particles. Small mass moves faster. KE=1/2mv 2 KE=1/2mv 2

9. Energy in states of matter Hi energy & velocity - Low attractive forces & density Hi energy & velocity - Low attractive forces & density Gas Gas Energy Liquid Energy Energy Liquid Energy Released In Solid Solid Low energy & velocity - Hi attractive forces & density Low energy & velocity - Hi attractive forces & density

10. Thermal expansion – increase in the size of a substance when the temperature increases: (which decreases density) Thermal expansion – increase in the size of a substance when the temperature increases: (which decreases density) The size of a substance will then decrease when the temperature decreases The size of a substance will then decrease when the temperature decreases Expansion and contraction occur in most solids, liquids, and gases Expansion and contraction occur in most solids, liquids, and gases Water is an exception because it expands as it becomes a solid: that’s why ice floats Water is an exception because it expands as it becomes a solid: that’s why ice floats

11. Behavior of Gases Pressure is measured in units called Pascal (Pa) Pressure is measured in units called Pascal (Pa) Collisions of particles in air result in atmospheric pressure Collisions of particles in air result in atmospheric pressure Moving particles colliding with the inside walls of a container result in gas pressure Moving particles colliding with the inside walls of a container result in gas pressure

12. Units of Pressure Atmospheres; torrs; millimeters of Mercury; kiloPascals; pounds per square inch Atmospheres; torrs; millimeters of Mercury; kiloPascals; pounds per square inch 1 atm = 760 torr = 760 mmHg = 101.3 kPa = 14.7 psi

13. Dalton’s Law of Partial Pressure The total pressure of a mixture of gases is equal to the partial pressures of the gas all added together The total pressure of a mixture of gases is equal to the partial pressures of the gas all added together P T = P 1 + P 2 + P 3 + … *Must be in the same Pressure Units

14. Ex. 1) Calculate the total pressure if 2.0 atm of gas A and 7.0 atm of gas B are mixed in a closed container.

15. Ex. 2) Some noble gases are stored in a container. If the individual pressures are P Ne = 450. mmHg, P He = 1.266 psi and P Kr = 70.2 kPa, what is the total pressure of the gases in atm?

16. Ex. 3) Helium and argon are in a gas chamber. The total pressure is 834 mmHg. If the pressure of Helium is 0.722 atm, what is the partial pressure of Argon in mmHg?

17. Boyle’s Law Boyle’s Law – relates pressure and volume Volume decreases as pressure increases Volume decreases as pressure increases Pressure decreases as volume increases Pressure decreases as volume increases Pressure multiplied by volume is always equal to a constant if the temperature is constant Pressure multiplied by volume is always equal to a constant if the temperature is constant P 1 V 1 = P 2 V 2 Inversely related

18. http://www.lerc.nasa.gov/WWW/K-12/airplane/aboyle.html Boyle’s Law

19. Charles’s Law Charles’s Law – relates volume and temperature At a constant pressure, volume increases as temperature increases At a constant pressure, volume increases as temperature increases At a constant pressure volume decreases as temperature decreases At a constant pressure volume decreases as temperature decreases V 1 = V 2 T 1 T 2 T 1 T 2 Directly Related

20. Charles’s Law http://www.lerc.nasa.gov/WWW/K-12/airplane/aglussac.html

21. Avogadro’s Law Avogadro’s Law – relates volume and moles, n. At a constant pressure, volume increases as moles increase. At a constant pressure, volume increases as moles increase. At a constant pressure, volume decreases as moles decrease. At a constant pressure, volume decreases as moles decrease. V 1 = V 2 n 1 n 2 n 1 n 2 Directly Related

22. Kelvin Scale!!!!! All gas laws involving a temperature: must use the Kelvin temperature scale. All gas laws involving a temperature: must use the Kelvin temperature scale. Absolute zero, the lowest point on the Kelvin scale, Theoretical value: point of zero volume and zero KE, all motion stops Absolute zero, the lowest point on the Kelvin scale, Theoretical value: point of zero volume and zero KE, all motion stops 0 °C = 273 K, and one degree Celsius is equal in size to one unit of Kelvin 0 °C = 273 K, and one degree Celsius is equal in size to one unit of Kelvin This is considered to be Standard Temperature for Gases This is considered to be Standard Temperature for Gases T K = T C + 273T C = T K - 273