What is an ideal Gas?

​An ideal gas is a gas in which both the volume of molecules and forces between the molecules are so small that they have no effect on the behavior of the gas.

There are no intermolecular forces of attraction between the particles of an ideal gas.

When do the ideal gas laws break down?

• very large molecules

• high pressure and low temperatures (this is when intermolecular forces will have more impact on behavior of the molecules

Ideal Gas Law: intro watch the intro video (the link is on the next slide)

Gas Laws - Ideal Gas Law

The Masterful Educator

PV = nRT

Ideal Gas Law - relates the pressure, volume, number of moles, and
temperature of a gas. R is the ideal gas constant.

Ideal Gas Constant
You have to pay attention to which units your pressure, volume, and
temperature are in, as they will dictate which value of R is needed.

Ideal Gas Law: Practice problems with me. The slides after the video are the problems.

Ex 1: What volume would be occupied by 0.625 mol
of hydrogen at 942 torr at 37.0 °C?

Formula:

P=

V=

n=

R=

T=

Ex 2: How many moles of gas fill a 2,200 mL vessel
with a pressure of 121.2 KPa at 25.0 °C?

Formula:

P=

V=

n=

R=

T=

Ex 3: What pressure will be exerted by 14.7 g of
oxygen gas at 25°C if it is contained in a vessel
whose volume is 650 mL?

Formula:

P=

V=

n=

R=

T=

1) A balloon contains 25.02 g of helium gas at room
temperature (22 °C) and occupies a volume of 75.0 L.
How much pressure does the He gas exert on the walls of
the balloon?

Formula:

P=

V=

n=

R=

T=

2) If 2.4 moles of a gas is held at a temperature of
97°C and in a container with a volume of 1,246 mL,
what is the pressure of the gas?

Formula:

P=

V=

n=

R=

T=

3) What volume will 2.50 mol of hydrogen (H2)
occupy at -20.0°C and 780 mmHg?

Formula:

P=

V=

n=

R=

T=

4) How many grams of sulfur dioxide are held inside
a 674 mL metal canister that has an internal
pressure of 1.25 atm and a temperature of 40.0°C?

Formula:

P=

V=

n=

R=

T=

5) At what temperature will a 0.450 L vessel hold
176 grams of carbon dioxide gas at a pressure of
1.25 atm?

Formula:

P=

V=

n=

R=

T=

6) An incandescent light bulb has a volume of 2.6 L
at 0.0°C and 1.12 x 105Pa contains how many moles
of gas?

Formula:

P=

V=

n=

R=

T=

7) At what temperature will 2.5 mol nitrogen gas
exert a pressure of 10.0 atm in a 2.0 L container?

Formula:

P=

V=

n=

R=

T=

8) What pressure will be exerted by 25 g of CO2 at a
temperature of 25⁰C and a volume of 0.5 L?

Formula:

P=

V=

n=

R=

T=