Name: _KEY________________ Date: _____________________ Period: _______

Solids, Liquids and Gases
1. Regarding the following characteristics how are liquids different from gases?
a. Expansion
Liquids have limited expansion. Gases will expand to fill the container they are in. b. Shape
Liquids and gases have no definite shape.
c. Volume
Liquids maintain volume while gases expand to fill the volume of their container.
d. Compressibility
Gases have high compressibility while liquids have low compressibility
e. Density
Gases have low densities while liquids have high densities relative to gases.
f. Mixing
Gases: Complete and Uniform
Liquids: Slow mixing
2. Describe how the presence of a constant vapor pressure is an example of a dynamic equilibrium. Constant vapor pressure means that the system has reached dynamic equilibrium since the rate of the liquid particles becoming a gas is equal to the rate of the particles of gas becoming a liquid.
3. Why is evaporation an endothermic process?
In order to change from a liquid to a gas requires the absorption of energy.
4. Why is the boiling point of water lower at high altitudes, compared to its normal 100°C?
At higher altitude there is less atmospheric pressure and so the water boils at a lower temperature. 5. Why is the boiling point of water higher at lower altitudes, compared to its normal
100°C?
At altitudes below sea level there is more atmospheric pressure and water boils at a higher temperature. 6. Regarding the fallowing characteristics how are solids different from liquids?
a. Expansion
Solid: Zero Expansion
Liquid: Limited
b. Shape
Solid: Definite
Liquid: no definite shape
c. Density
Solid: High
Liquid: High
d. Mixing
Solid: Severely limited
Liquid: Mixing is slow
7. What is the difference between crystalline solids and amorphous solid. (Pay particular attention to their differences relative to how they melt.)

Name: _KEY________________ Date: _____________________ Period: _______
A crystalline solid has a definite geometric shape and it will have a very precise melting point. Amorphous solids do not have the order of crystals and have a melting range and not a precise melting point.
8. Why does ice (solid water) have a lower density than liquid water?
The bent shape of the water molecule gives it a higher density as a liquid because the molecule are able to move closer together, while as a solid the molecules are not able to stack as closely together making ice less dense.
9. Describe the behavior of the molecules in a liquid. Explain this behavior in terms of intermolecular forces.
Liquid have motion associated with the particles, the energy of the motion does not exceed the strength of the intermolecular forces that hold the liquid together.
Complete each of the sentences below.
10. The stronger the intermolecular forces in a liquid, the ____higher___ its boiling point.
11. The state of a substance at