1. Ch. 10: Physical Properties of Gases
10.3 Gas Laws:
Relationships between volume, temperature, pressure, and amount of gas.

2. Boyle’s Law: P and V as one increases, the other decreases
inversely proportional
pressure is caused by moving molecules hitting container walls
If V is decreased and the # of molecules stays constant, there will be more molecules hitting the walls per unit

3. Boyle’s Law: P and V
Boyle’s Law: the V of fixed mass of gas varies inversely with P at a constant T.
PV = k
k is a constant for a certain sample of gas that depends on the mass of gas and T
What kind of graph is V vs. P?
If we have a set of new conditions for the same sample of gas, they will have same k so:

4. Boyle’s Law

5. Boyle’s Law: P and V Discovered by Irish chemist, Robert Boyle
Used a J-shaped tube to experiment with varying pressures in multistory home and effects on volume of enclosed gas

6. Example: Boyle’s Law
Consider a 1.53-L sample of gaseous SO2 at a pressure of 5.6 x 103 Pa. If the pressure is changed to 1.5 x 104 Pa at constant temperature, what will be the new volume of the gas?

7. Charles’ Law: V and T if P is constant, gases expand when heated
when T increases, gas molecules move faster and collide with the walls more often and with greater force
to keep the P constant, the V must increase

8. Charles’ Law: V and T
Problem: if we use Celsius, we could end up with negative values from calculations in gas laws for volumes
we need a T system with no negative values: Kelvin Temperature Scale
starts at ° C = absolute zero = 0 K
lowest possible temperature
balloon going into liquid nitrogen

9. Charles’ Law: V and T
Charles’ Law: the V of fixed mass of gas at constant P varies directly with Kelvin T.
V = kT
k is a constant for a certain sample of gas that depends on the mass of gas and P
What kind of graph is V vs. T?
If we have a set of new conditions for the same sample of gas, they will have same k so:

10. Charles’ Law discovered by French physicist, Jacques Charles in 1787
first person to fill balloon with hydrogen gas and make solo balloon flight

11. Example: Charles’ Law & Temp.
A sample of gas at 15°C and 1 atm has a volume of 2.58 L. What volume will this gas occupy at 38°C and 1 atm?