The Ideal Gas Law

2 Ideal Gas Definition Ideal Gas: a hypothetical gas composed of particles that have zero size, travel in straight lines, and have no attraction to each other (zero intermolecular force)

3 Four variables define an ideal gaseous system: 1) According to Boyle’s law, the volume of a gas is inversely proportional to the pressure, v α 1/p 2) Charles’s law, the volume of a gas is directly proportional to the absolute temperature, v α T

4 Four variables define an ideal gaseous system: 3) According to Gay-Lussac’s law, the pressure of a gas is directly proportional to the absolute Kelvin temperature, p α T 4) The greater the amount of gas, in moles, at the same temperature and pressure, the greater the volume. (e.g. blowing up a balloon, more air you put in, the bigger the balloon gets)

5 Mathematical relationship v α 1/p x T x n v = (constant, R) x 1/p x T x n v = nRT p pv = nRT

6 R = gas constant ; relates the pressure in kPa, volume in litres, amount in moles, and temperature in Kelvin of an ideal gas. R = 8.31 kPa ● L 1 mol ● K

7 Properties of an Ideal Gas v-T and p-T graphs are perfectly straight lines gas does not condense to a liquid when cooked gas volume = 0 at absolute zero pv = nRT gas particles are point size (volume of particle=0) gas particles do not attract each other

8 The Ideal Gas Law PRACTICE! If you had 0.78 g of hydrogen at 22 o C and 125 kPa. What volume of hydrogen would be expected?

9 Learning Checkpoint Assigned Questions: p. 445 Practice UC # 3, 4, 5, 6