5 things you should know about PV=nRT aka the IDEAL GAS LAW

1. Pressure

  • Definition:
  • A measure of how forcefully and frequently particles collide with each other and the walls of their container
  • Units:
  • 760 mmHg = 101.3 kPa = 1.00 atm
  • Other notes:
  • Directly proportional to temperature and number of moles (as temperature or number of moles increases, pressure also increases)
  • Inversely proportional to volume (as volume decreases, pressure increases)

2. Volume

  • Definition:
  • The space that a substance occupies
  • Units:
  • Always Liters (1000 mL = 1L)
  • Other notes:
  • Directly proportional to temperature and number of moles (as temperature or number of moles increases, volume also increases)
  • Inversely proportional to pressure (as volume increases, pressure decreases)

3. number of Moles

  • Definition:
  • A measure of the number of particles of a gas or liquid
  • Units:
  • moles (1 mole = 6.02 x 10 particles)
  • if quantity of substance is given in grams, divide by molar mass
  • Other notes:
  • Directly proportional to pressure and volume (as number of moles increases, volume and pressure also increase)

4. R (constant)

  • Definition:
  • A constant number used to make all the units line up and give a proper answer
  • Units:
  • 62.4 mmHg x L / moles x K
  • 8.31 kPa x L / moles x K
  • 0.0821 atm x L / moles x K
  • Other notes:
  • R?s value and units change depending on the unit of pressure

5. Temperature

  • Definition:
  • the average kinetic energy of all the particles in a substance
  • Units:
  • degrees Kelvin (NOT CELSIUS)
  • K = C + 273
  • Other notes:
  • Directly proportional to volume and pressure (as temperature increases, volume and/or pressure also increase)
  • kinetic energy depends on the velocity of particles and mass of particles (KE = 1/2 mv)
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