Phase Change Exam
Name:____________Teacher’s Key_______________
1. In the space provided, please draw how the molecules in a substance are arranged
in the three states of matter. (Order not important when grading)
Solid
I will need to see a model of
the molecules where the
molecules are clearly the
closest together of all the
drawings. They may be
touching but should go over
when handing back that the
molecules aren’t actually
touching.
Liquid
Must clearly be the middle of
the three drawings. Obviously
further apart than the solid
but much closer than the gas.
Gas
Must clearly have the most
space of the three drawings.
2. Explain how kinetic energy influences temperature.
In their answer, students should discuss how temperature increase is a result of the increase
of kinetic energy at the atomic level. As the motion of the particles increase so too does the
temperature.
3. On the graph below, graph the temperature of a substance as it changes phases.
4. Describe Rutherford’s Gold Foil experiment. What was his major discovery?
Alpha particles were fired at a sheet of gold foil with a detecting screen around it to measure
deflections. The deflections suggested that there was a massive, central, positively charged
nucleus surrounded by negatively charged electrons.
5. From the symbol below, tell me the following about Carbon-12: a) number of
protons, b) number of electrons, c) number of neutrons, d) atomic mass. (Hint:
Assume that the atom is neutral).
6
C
12.01
a)6, b)6, c)6, d)12.01amu
Phase Change Exam
6. When a 2kg block of ice transitions to liquid, what is the mass of the liquid relative
to the original block of ice?
a. The mass of the liquid is less than the mass of the ice.
b. The mass of the liquid is the same as the mass of the ice.
c. The mass of the liquid is greater than the mass of the ice.
7. Water cools from 80°F to 30°F. During this time, what happens to the motion of the
molecules?
a. The motion of the molecules stops.
b. The motion of the molecules increases.
c. The motion of the molecules decreases.
d. The motion of the molecules remains the same.
8. Which of the following is an example of a physical change?
a. Iron exposed to air produces rust.
b. Hydrogen combined with oxygen forms water.
c. Sulfur combined with oxygen produces sulfur dioxide.
d. Liquid nitrogen exposed to air becomes nitrogen gas.
9. Which of the following is an example of chemical change?
a. Salt dissolves into water.
b. Iron exposed to air produces rust.
c. Liquid nitrogen exposed to air becomes nitrogen gas.
d. All of the above.
10. The proton is:
a. Less massive than a neutron.
b. More massive than an electron.
c. Less massive than an electron.
d. The same mass as an electron.
Matching Questions: Use the word bank below and match them with the most appropriate
blank space.
Sublimation
Freezing
Evaporation
Condensation
Melting
Phase Change
Proton
Neutron
Electron
Nucleus
Orbital
Matter
Neutral
Positive
Negative
1. The process by which a gas changes to a liquid is called Condensation.
2. The concept of Phase Change describes the overall transition of matter from one
state to another.
3. The process of Melting describes the transition of matter from a solid to a liquid.
4. When a substance transitions directly from a solid to a gas the process is known as
Sublimation.
5. The Proton has a Positive charge and is found in the Nucleus. These particles are
responsible for determining the identity of an element.
6. When matter transitions from a liquid to a gas, the process is called Evaporation.
7. The Neutron has a neutral charge and is found in the Nucleus. These particles are
added and subtracted in the creation of isotopes.
8. The electron has a negative charge and is found in the orbital. These particles are
used in bonding and are added and subtracted in ionization.
9. Freezing is the transition of a liquid to a solid.
Essay Questions: Answer the following two (2) essay questions. Use the back of the page if
necessary. You may use illustrations, however, you must take the time to explain any
illustrations you use.
1. Follow a pollutant through the water cycle and explain how it facilitates Acid Rain.
Be sure to discuss Conservation of matter.
Describe what is wrong with the atomic model below. In your answer, name the
atomic model depicted and be sure to provide what is now accepted as an atomic
model and the research that supports it. (Hint: Think of gold. Blue background is
positive)