Chapter 13 Review

Video Review

Key Concept Summary

TA Summary


The tiny constituent particles of which matter is composed.
A measure of average kinetic energy of the molecules that make up an object.
The constant, irregular motion of very fine particles suspended in a fluid and observed with a microscope.
The transfer of microscopic kinetic energy between two solid objects (a hot one and a cold one) that are in physical contact with each other.
Model that explains the behavior of gases observed by Maxwell.
Force per unit area.


Pressure in a hot tire is greater than the pressure when the tire is cold.
For a given material, the solid state has a higher internal energy than the gaseous state.
The molecular model is limited in that it cannot explain the color of an object.
Heat is the amount of energy associated with electrical potential energy.
In the molecular model, molecules are assumed to move according to special laws of motion which are different from how large objects move.
According to Maxwell, all of the gas molecules in a balloon are traveling at the same speed.


Between two objects, heat always travels
For nearly all substances, the density of physical states increases in which order?
The average distance between molecules in states of matter (solid, liquid, gas) increase in which order?
If a large bucket of water and a small bucket of water have the same temperature,
Heat conduction occurs from a warm room through a closed window on a cold day because
Evaporation of water from the skin has a cooling effect. This is because
Which of the following best describes the behavior of molecules in the molecular model?
Temperature is a measurement of:
Gas pressure is caused by:
Which of the following will increase the air pressure in a car tire?
When a gas molecule collides with a rigid wall, how does the force it exerts on the wall compare to the force the wall exerts on the molecule?
Suppose two identical airtight containers are connected to each other by a thin tube. They both start out at room temperature, but one container is placed in a pan of boiling water, while the other is placed in a container of ice water. What happens to the air trapped in the containers?
Air is made up of several different types of molecules. Which move the fastest.
As an ice cube changes from a solid at 0 °C to a liquid at the same temperature, what happens to the kinetic energy of the molecules?
If the volume of a gas is decreased, what happens to the temperature of that gas?
Two identical containers of gas are at identical pressures, but container 1 has twice as many gas molecules inside as container 2. What can you conclude about the containers?
What would Robert Brown have observed if he increased the sample temperature while looking through his microscope?

Free Response

  1. Using the Molecular Model, explain why gases readily change volume when pressure is applied, while liquids and solids do not change volume appreciably, unless under enormous pressure.
  2. Use the Molecular Model to explain each observation:
    • The density of solid nitrogen molecules is greater than the density of nitrogen molecules in air.
    • Heat flows from hot objects to colder ones.
    • Perfume spilled at one end of a room can be smelled at the other end after a few seconds.
  3. Your neighbor knocks at your door and asks you to explain something. She bought a helium-filled balloon for her daughter in a warm grocery store. When she put it in her car on a cold January day, the balloon shrank and she thought the balloon had sprung a leak. But the balloon returned to its original size when she took it into her warm house. What explanation can you give based on the molecular model?
  4. Figure 13.5 in the textbook illustrates how the distribution of molecular speeds varies with mass of the gas particles for helium, nitrogen, and argon. Helium atoms have a mass of 4 units, nitrogen molecules have mass 28, and argon atoms have mass 40. Sketch what the graph might look like for oxygen molecules, if oxygen molecules have a mass of 32. The most important characteristics of the distribution are the most popular speed, the fraction of molecules with that speed, and the overall width of the distribution.

Do the following:

Identify the portions of the graph in Figure 13.8 in the textbook where only one state of matter is present (e.g., only solid, only liquid, or only gas). Describe what happens to the temperature during these portions of the graph as time and total energy increase. (If you were looking at a thermometer, what would you see happening?) From your observation of the temperature change, what can you conclude about the kinetic energy of the matter during these processes? That is, does the kinetic energy increase or decrease as the total energy increases?

Now look at the segments when two states of matter are present (solid & liquid, liquid & gas). Describe the temperature behavior within these segments as time and total energy increases. What can you conclude about the change in kinetic energy based upon the temperature behavior?

Hopefully, you have identified stages in the process where the kinetic energy is constant but the total energy is increasing. How can you explain this? Think about what happens to the average distance between molecules as you go from state to state. What kind of energy is associated with the relative positions of particles?

The details of Figure 13.8 apply to changes of state for many substances other than water. Pick one of the substances (other than water) in Table 12.1 in the textbook and sketch a graph like Figure 13.8 for your substance. Things to consider: At what temperatures will you have plateaus? Between what temperatures will you have sloping lines?