Wake-up
1. Write the formula for Charles Law.
2. Write the formula for Boyle’s Law.
3. Bromine gas has a pressure of 536.8 mmHg.
When it is dispensed into a new container,
its pressure becomes 784.6 mmHg with a
new volume of 412.3 mL. What was the
original volume?
4. Identify the Law for #3.
Ideal Gas Laws
What is the IDEAL GAS LAW?
What are the variables involved?
What is Avogadro’s Law and didn’t I already learn
about him with the mole?
What is an Ideal Gas?
1. Made up of molecules which are in constant
random motion in straight lines.
What is an Ideal Gas?
2. The volume of the molecules is negligibly small
compared to the volume occupied by the gas
What is an Ideal Gas?
3. All collisions are perfectly elastic. (There is no
loss of kinetic energy during the collision.)
Ideal Gas Law Equation
Equation is on the Reference Table
What is R?
R is called the Ideal Gas Constant or Universal Gas
Constant
Gas Constant Value
See Reference Table
0.0821
62.4
8.314
L atm
mole K
L mmHg
mole K
L kPa
mole K
What is the difference between each constant?
Gas Constant Value
See Reference Table
0.0821
62.4
8.314
L atm
mole K
L mmHg
mole K
L kPa
mole K
Units of Pressure – Select constant by units used in
problem
Proper units of Ideal Gas Formula
When using the Ideal Gas Formula, use correct
units!!! Check units before use equation.
P = Pressure (atm)
V = Volume (L)
n = Number of moles (mol)
R = Gas constant L atm
mol K
T = Temperature (K)
Example #1
How many moles of N2 are in a 750 mL vessel at
26 degrees Celsius and 625 mm Hg?
P = 625 mmHg
V = 750mL  0.750 L
n=?
R = 62.4 L mmHg
mol K
T = 26°C  299 K
(625)(0.75) = (n)(62.4)(299)
468.75 = (18657.6)(n)
N = 0.025 mol
Example #2
If I have 17 moles of gas at a temperature of 67 0C, and a
volume of 88.89 liters, what is the pressure (kPa) of the gas?
P = ? kPa
V = 88.89 L
n = 17 mol
R = 8.314 L kPa
mol K
T = 67°C  340 K
(P)(88.89) = (17)(8.314)(340)
(P)(88.89) = (48054.92)
P = 540.6 kPa
Example #3
If I have 7.7 moles of gas at a pressure of 0.09 atm and at a
temperature of 56 0C, what is the volume of the container
that the gas is in?
P = 0.09 atm
V=?
n = 7.7 mol
R = 0.0821 L atm
mol K
T = 56°C  329 K
(0.09)(V) = (7.7)(0.0821)(329)
(0.09)(V) = (207.98)
N = 2310.9 L