10.1 The Kinetic Molecular Theory of Matter

Which of the following gases would you expect to deviate significantly from ideal behavior: He, O2, H2O, N2, HCl, or NH3?

H2O, HCl, and NH3, because they are polar

Diffusion between two gases occurs most rapidly if the gases are at

High temperature and the molecules are small

According to the kinetic-molecular theory, how does a gas expand?

Its particles move greater distances

How does the kinetic-molecular theory explain the pressure exerted by gases?

Pressure exerted by gases is caused by collisions of the gas molecules with the walls of the container.

The kinetic-molecular theory explains the properties of solids, liquids, and gases in terms of the energy of the particles and

The forces that act between the particles

Unlike in an ideal gas, in a real gas

The particles exert attractive forces on each other

What happens to gas particles when a gas is heated?

They move more rapidly, increasing their average kinetic energy

Describe the conditions under which a real gas is most likely to behave ideally.

Under high temperature and low pressure, real gases approach ideal gas behavior.

What is a real gas?

is a gas that does not behave completely according to the assumptions of the kinetic-molecular theory.

What is an ideal gas?

is a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory.

What is the kinetic Molecular theory?

is a theory that explains that the behavior of physical systems depends on the combined actions of the molecules constituting the system.

What idea is the kinetic Molecular theory based on?

it is based on the idea that particles of matter are always in motion.

Which is an example of gas diffusion?

the odor of perfume spreading throughout a room

Which substance has the lowest density?

H2O(g)

CRITICAL THINKING: Molecules of hydrogen escape from Earth, but molecules of oxygen and nitrogen are held to the surface and remain in the atmosphere. Explain.

The lower mass of hydrogen molecules means that they are travelling at higher speeds, so fewer of them remain captured by gravity.

Which is an example of effusion?

air slowly escaping from a pinhole in a tire

Define effusion

is a process by which gas particles pass through a tiny opening

Define diffusion

is a spontaneous mixing of the particles of two substances caused by their random motion

What is an elastic collision?

is one in which there is no net loss of total kinetic energy.

If a gas with an odor is released in a room, it quickly can be detected across the room because it

Diffuses

By which process do gases take the shape of their container?

Expansion

The density of a substance undergoes the greatest change when the substance changes from a

Liquid to a gas

According to the kinetic-molecular theory, particles of matter are in motion in

Solids, liquids, and gases.

What determines the average kinetic energy of the molecules of any gas?

Temperature

An ideal gas is a hypothetical gas

That conforms to all of the assumptions of the kinetic theory

According to the kinetic-molecular theory, which substances are made of particles?

All matter

A real gas

Does not obey all the assumptions of the kinetic-molecular theory

What happens to gas particles when a gas is compressed?

They are pushed closer together

Use the kinetic-molecular theory to explain the following properties of gases: A) Expansion B) Fluidity C) Low density & Compressibility D) Diffusion

A) Expansion: Gas particles move rapidly in all directions without significant attraction between them. B) Fluidity: Attractive forces between gas particles are too weak to hold the particles in a rigid structure. C) Low density & compressibility: Gas particles are farther apart than they are in any other state. D) Diffusion: Gas particles are in continuous and random motion.

What are the physical properties of gases?

A) Gas particles are much farther apart than the particles in solids and liquids. B) Gas particles move freely almost independently of one another. C) Unlike solids and liquids, gases fill whatever container they are in. D) Gases are fluids and can flow easily.

What are the hypothesis "Assumptions" of the kinetic molecular theory?

A) Gases are composed of a large number of particles that behave like hard, spherical objects in a state of constant, rapid, random motion. B) These particles move in a straight line until they collide with another particle or the walls of the container. C) These particles are much smaller than the distance between particles. Most of the volume of a gas is therefore empty space. D) There is no force of attraction between gas particles or between the particles and the walls of the container. E) Collisions between gas particles or collisions with the walls of the container are perfectly elastic. None of the energy of a gas particle is lost when it collides with another particle or with the walls of the container. F) The average kinetic energy of a collection of gas particles depends on the temperature of the gas and nothing else.

The kinetic-molecular theory states that ideal gas molecules

Are in constant, rapid, random motion.

Two gases have the same temperature but different pressures. The kinetic-molecular theory does not predict that

Both gases have the same densities.