Gas Laws

Boyle's Law

For a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure.

Charles's Law

The volume of a fixed mass of gas is directly proportional to its Kelvin temperature, if the pressure is kept constant.

Dalton's Law

At constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases.

Graham's Law

The rate at which a gas will effuse is inversely proportional to the square root of the gas's molar
mass.

Gay-Lussac's Law

The pressure of a gas is directly proportional to its Kelvin temperature if the volume is kept constant.

ideal gas law

P x V = n x R x T

effusion

the escape of gas through a small hole in a container

compressibility

a measure of how much the volume of matter decreases under pressure

diffusion

tendency of molecules to move to regions of lower concentration

partial pressure

the pressure exerted by a gas in a mixture

Why is a gas easier to compress than a liquid or a solid?

The volume of a gas's particles is small compared to the overall volume of the gas.

Why does the pressure inside a container of gas increase if more gas is added to the container?

There is an increase in the number of collisions between particles and the walls of the container.

If the volume of a container of gas is reduced, what will happen to the pressure inside the container?

The pressure will increase.

If a balloon is squeezed, what happens to the pressure of the gas inside the balloon?

It increases.

What happens to the temperature of a gas when it is compressed?

The temperature increases.

As the temperature of the gas in a balloon decreases, which of the following occurs?

The volume of the balloon increases.

What happens to the pressure of a gas inside a container if the temperature of the gas decreases?

The pressure decreases.

If 4 moles of gas are added to a container that already holds 1 mole of gas, how will the pressure change inside the container?

The pressure will be five times higher.

Why does air escape from a tire when the tire valve is opened?

The pressure outside the tire is lower than the pressure inside the tire.

Which of these changes would NOT cause an increase in the pressure of a contained gas?

The volume of the container is increased.

When the Kelvin temperature of an enclosed gas doubles, the particles of the gas ____.

move faster

The volume of a gas is doubled while the temperature is held constant. How does the gas pressure
change?

It is reduced by one half.

When the temperature and number of particles of a gas are constant, which of the following is also constant?

the product of the pressure and volume

If a balloon is heated, what happens to the volume of the air in the balloon if the pressure is constant?

It increases.

If a balloon is heated, what happens to the pressure of the air inside the balloon if the volume remains constant?

It increases.

When the volume and number of particles of a gas are constant, which of the following is also constant?

the ratio of the pressure and temperature in kelvins

What happens when a piston is used to decrease the volume of a contained gas?

Gas particles become compressed.

The combined gas law relates which of the following?

temperature, pressure, and volume

What does the ideal gas law allow a scientist to calculate that the other gas laws do not?

number of moles

At a certain temperature and pressure, 0.20 mol of carbon dioxide has a volume of 3.1 L. A 3.1-L sample of hydrogen at the same temperature and pressure ____.

contains the same number of molecules

Which law can be used to calculate the number of moles of a contained gas?

ideal gas law

Which of the following is constant for 1 mole of any ideal gas?

PV / T

Under what conditions of temperature and pressure is the behavior of real gases most like that of ideal gases?

low temperature and high pressure

What happens to the partial pressure of oxygen in a sample of air if the temperature is increased?

It increases.

If the volume of a container of air is reduced by one-half, what happens to the partial pressure of oxygen within the container?

It is doubled.

Which of the following gases will effuse the most rapidly?

hydrogen

Which of the following gases is the best choice for inflating a balloon that must remain inflated for a long period of time?

argon

As the temperature of a fixed volume of a gas increases, the pressure will ____.

increase

A gas occupies a volume of 2.4 L at 14.1 kPa. What volume will the gas occupy at 84.6 kPa?

0.40 L

A sample of gas occupies 17 mL at -112�C. What volume does the sample occupy at 70�C?

36 mL

If a balloon containing 3000 L of gas at 39�C and 99 kPa rises to an altitude where the pressure is 45.5 kPa and the temperature is 16�C, the volume of the balloon under these new conditions would be calculated using the following conversion factor ratios

3000 L x (289 / 312) x (99 / 45.5)

A breathing mixture used by deep-sea divers contains helium, oxygen, and carbon dioxide. What is the partial pressure of oxygen at 101.4 kPa if PHe = 82.5 kPa and PCO? = 0.4 kPa?

18.5 kPa

The tendency of molecules to move toward areas of lower concentration is called ____.

diffusion