Science10 - 4th Quarter Mastery

• States of Matter


  • Solid
  • Liquid
  • Gas
• Factors determining state


  • Forces (inter/intramolecular) holding particles together
  • Kinetic energy present
• Kinetic energy


  Tends to 'pull' particles apart
• Kinetic Energy


  • States of Matter
  • Temperature
• Gases


  • Have higher kinetic energy
  • Expand to fill any container
  • Random motion, no attraction
  • Fluids, no attraction
  • Very low densities, no volume
  • Can be compressed
  • Undergo diffusion and effusion, move in random motion
• Kinetic Molecular Theory of Ideal Gases

  • Elastic collision (will exchange energy with each other)
  • In constant motion
  • Don't attract/repel each other
  • Have an average KE directly related to temperature
  • No volume
• Real Gases


  • Have their own volume
  • Attract each other
• STP (Standard Temperature and Pressure)


  Pressure = force/area
• Atmospheric Pressure


  Gas molecules in the atmosphere are pulled towards Earth due to gravity
• Barometer


  Measures atmospheric pressure
• Units of Pressure


  • SAP (Standard Atmospheric Pressure) = 101.325 kPA
  • 1 atm
  • 760 mm Hg
  • 760 torr
  • 147 psi
• Always use Absolute temperature (Kelvin)
• °C


  K
• Not everything freezes at 0°C but all substances, motion stops at 0K
• Boyle's Law


  • Pressure and volume of a gas are inversely proportional (constant mass and temperature)
  • P1 V1 = P2 V2
• Boyle's Law Example

  • A helium balloon has a volume of 735 mL at ground level. The balloon is transported to an elevation of 5 km, where the pressure is 0.8 atm. At this altitude, the gas occupies a volume of 1286 mL assuming that the temperature is constant, what was the ground level pressure?

  Solution:

  
  

  Given: P1 = ?, V1 = 735 mL, P2 = 0.8 atm, V2 = 1286 mL

  
  

  P1 V1 = P2 V2

  P1 (735 mL) = (0.8 atm) (1286 mL)

  P1 = 1.39 ≈ 1.4 atm
• Barometer

  measures atmospheric pressure
• identify the questions and put solutions