Key Concepts
Which two variables are proportional to each other in Gay Lussac's Law?
Pressure and temperature
What is the general formula for Gay Lussac's Law?
P1/T1=P2/T2
Why can aerosol cans explode when heated?
When heated the internal pressure rises causing the can to explode.
This temperature scale must be used when applying Gay Lussac's Law.
In a pressure vs. temperature (Kelvin) graph for Gay-Lussac’s Law, what kind of line is produced?
Linear, a straight line.
Which variable is kept constant in order for Gay Lussacs Law to apply?
Volume
What does P1 represent in the general equation?
P1 represents the initial pressure.
Why does tire pressure increase slightly on a hot day?
The higher heat from the outside causes the tires pressure to rise.
To convert from Celsius to Kelvin you must use which number?
273.15
As temperature increases, pressure______
a) stays the same
b)decreases
c) increases
c) increases
What happens to the pressure of gas when its temperature increases? (at a constant volume)
The pressure increases
In the general formula, what does T2 represent?
The final temperature.
Why are gas tanks not filled completely in hot weather?
It prevents any flammable gas from overflowing.
A gas has a temperature of -10 degrees Celsius. What is this in Kelvin?
263.15
If the temperature is halved (in Kelvin), what happens to the pressure?
The pressure is halved as well.
How do you convert temperature from Celsius to Kelvin?
by adding 273.15, 0 degrees celsius in kelvin.
A rigid container holds a gas at a pressure of 2.0 atm and a temperature of 300 K.
If the temperature increases to 450 K, what will the new pressure be?
3.0 atm or 303.9 kPa
What happens to the pressure of a sealed container placed in a freezer?
The pressure decreases.
Why would using Celsius instead of Kelvin cause errors in Gay-Lussac’s Law calculations?
Celsius can be zero or negative, which breaks the direct proportional relationship between pressure and temperature; Kelvin is an absolute scale.
Why must a pressure vs. temperature graph for Gay-Lussac’s Law pass through the origin?
Because at 0 K, the pressure would be 0, so the relationship starts at the origin.
Why must the volume stay constant for Gay Lussac's Law to apply?
If the volume were to change other effects may interfere with the direct proportionality of pressure and temperature.
A sealed steel tank contains nitrogen gas at a pressure of 150 kPa and a temperature of 25°C. The tank is heated until the pressure rises to 220 kPa.
T2 = 437 k
Why should you never heat a sealed container?
Any gas present will expand, causing the pressure to increase, risking explosion of the sealed container.
A gas is heated from 300 K to 600 K.
What happens to the pressure?
The pressure increases drastically.
Which statement best describes the relationship between pressure and temperature in Gay-Lussac’s Law?
Pressure is directly proportional to temperature (in Kelvin).