# 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)