Gas Law Notes

We follow the Kinetic Molecular Theory when we learn about the behavior and properties of gases. To fully understand the behaviors, we focus on four variables. As a review, the four variables are:

1) Pressure
2) Temperature
3) Volume
4) Amount

​

Four Variables

Categorize

Options (14)

the number of particles

unit is moles or mol

symbol is "n"

. $$\frac{force}{area}$$

create by particles colliding with the container

symbol is "P"

unit is atm

unit is kPa

average kinetic energy

symbol is "T"

units are °C and K

the amount of space

symbol is "V"

unit is L

Place the descriptive terms in the correct categories for the four variables.

Amount

Pressure

Temperature

Volume

We have been using amount (moles) and volume most of the year; however, there are special focus that needs to be made on pressure and temperature.

It is important to know how we experience pressure. Pressure occurs by particles colliding against another object. We measure pressure exerted by the gas by measuring how the particles collide with the container.

Make sure you have the information from the following slide in your notes.

​

Pressure

Match

Match the name of the unit with its symbol.

• atmosphere

• Pascal

• kiloPascal

• millimeters of mercury

• Torr

atm

Pa

kPA

mm Hg

Torr

• atm

• Pa

• kPA

• mm Hg

• Torr

Multiple Choice

What is the pressure in atmospheres of 450.2 kPa?

• 4.443 atm

• 45,610 atm

• 101.3 atm

• 0.009872 atm

Multiple Choice

What is the pressure in mm Hg of 450.2 kPa?

• 3377 mm Hg

• 60.02 mm Hg

• 7.501 mm Hg

• 0.1333 mm Hg

Although we are familiar with temperature, there is a special note about the temperature we use when making calculations for gases.

Scientists discovered that in order for calculations to be made for gases, the temperature needs to be in Kelvin (K), which starts at absolute zero.

This is requires a calculation because we always measure temperature in °C.

​

Temperature

Fill in the Blanks

The temperature of 75°C is equal to

K.

Fill in the Blanks

The temperature of 298 K is equal to

°C.

Multiple Choice

What unit of temperature is necessary when calculating gas problems?

• degrees Celsius

• degrees Fahrenheit

• Kelvin

• Depends on the thermometer.

Fill in the Blanks

A 0.400 mol sample of gas is contained in a rigid 22.4 L container. The pressure of the gas is 40.5 kPa at 273 K. What is the pressure of a 1.00 mol sample of the gas if the temperature of the container remains constant? (Hint: What is meant by a rigid container?)

Fill in the Blanks

If 25.0 mL of gas at constant T is compressed from 250. Torr to 1000. Torr, what is the new volume?

Fill in the Blanks

A sample of helium is kept at a constant volume of 600. mL and heated from 127.0 °C to 227 °C. What is the pressure of helium at the new temperature if the original pressure was 150. kPa?

Fill in the Blanks

A 450. mL sample of helium at constant pressure is heated from 27.0ºC to 127ºC.  What is the new volume?

These are four of the gas laws that we use when making calculations. We will make calculations using these gas laws and three others during this unit.

​

Gas Laws