1. GAS LAWS

2. Boyle’s Law At constant temperature,
the pressure and volume of a sample of gas are inversely proportional to each other.
as pressure increases, volume decreases
P V
as pressure decreases, volume increases
NASA Boyle’s Law Animation

3. Boyle’s Law Using the same gas at the same temperature: P1V1 = k1
If we change the Pressure, the Volume will change
and because P and V are inversely proportional to
each other: P2V2 = k1
Therefore: P1V1 = P2V2
Do Boyles Law problems on worksheet

4. Charles’ Law T V At constant pressure,
the volume of a fixed amount of gas is directly proportional to its absolute temperature.
as temperature increases, volume increases
T V
as temperature decreases, volume decreases
NASA Charles’ Law Animation

5. Charles’ Law The equation for a straight line is: y = m x + b
V = (slope) (T) + (y-intercept)
V = k T ( ????)
If we use absolute temperature (Kelvin scale)
y-intercept = 0
V = k2 (T) + 0
or V = k2 T

6. Charles’ Law
If we use Celsius temperature scale
V = k2 (T) + (some #)
**Therefore, when using any of the Gas Laws the Temperature MUST be in KELVIN
V1 = k2 V2 = k2
T1 T2
V1 = V2
T1 T2
Do Charles’ Law problems on worksheet

7. Combined Gas Law Boyle’s Law at constant temperature P1V1 = P2V2
Charles’ Law at constant pressure
V1 = V
T1 T2

8. Combined Gas Law Combined Gas Law (see Reference Table T) P1V1 = P2V2
T T2
Animations
Animated/Interactive Practice Problem

9. Avogadro’s Law k3 = 22.4 liters gas V = k3 n n = # moles
k3 = molar volume at STP (273K , 1 atm)
k3 = 22.4 liters gas
mole gas

10. Avogadro’s Law What volume does 2.0 moles CO2 gas occupy?
What volume does 3.5 moles Ne gas occupy?
What volume does 3.5 moles H2 gas occupy?

11. Dalton’s Partial Pressures
Dalton’s Law of Partial Pressures – the sum of the partial
pressures of all the components in a gas mixture is equal to
the total pressure of the gas mixture.
Pt = pa + pb + pc
Pt = total pressure
pa = partial pressure of component a
pb = partial pressure of component b
pc = partial pressure of component c

12. Dalton’s Partial Pressures
What is the total pressure exerted by the atmospheric gases if the
partial pressures of nitrogen, oxygen and argon are mm Hg,
162.8 mm Hg, and 0.5 mm Hg respectively?
A sealed container has 1 mole of helium and 2 moles of nitrogen at
30°C. When the total pressure of the mixture is 600. mmHg, what is
the partial pressure of nitrogen? What is the partial pressure of helium?
A mixture of 2.00 moles of H2, 3.00 moles of NH3, 4.00 moles of CO2
and 5.00 moles of N2 exerts a total pressure of 800. mmHg.
What is the partial pressure of each gas?

13. Dalton’s Partial Pressures
What is the total pressure exerted by the atmospheric gases if the
partial pressures of nitrogen, oxygen and argon are mm Hg,
162.8 mm Hg, and 0.5 mm Hg respectively?
A sealed container has 1 mole of helium and 2 moles of nitrogen at
30°C. When the total pressure of the mixture is 600. mmHg, what is
the partial pressure of nitrogen? What is the partial pressure of helium?
A mixture of 2.00 moles of H2, 3.00 moles of NH3, 4.00 moles of CO2
and 5.00 moles of N2 exerts a total pressure of 800. mmHg.
What is the partial pressure of each gas?

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