Name:__________________________________________________________________________________
Phase Changes and Phase Change Diagrams (Unit 2.3)
PHASE CHANGES
Important pieces of information to remember from the chart below: the name of each phase change, whether energy is
added or released from the phase account, what happens to the attraction between particles.
PHASE CHANGE DIAGRAMS
A phase diagram is a graph of pressure versus temperature that
shows the conditions necessary for a substance to be a solid, liquid,
or a gas. Each substance has a unique phase diagram. Notice that in
the diagram to the right, there are three regions (solid, liquid, gas)
separated by three curved lines. These lines represent the pressure
and temperature conditions at which two phases of a substance can
coexist. The point labeled T is the triple point. This is the pressure
and temperature at which all three phases of matter can exist at the
same time. On the graph to the right label all six phase changes.
gas
Directions: For each labeled point on the graph to the right, determine
the phase(s) of matter that exist.
A)______________________________________
C
B
A
B)______________________________________
D
C)______________________________________
D)______________________________________
E)______________________________________
E
Name:__________________________________________________________________________________
Directions: Look at the phase diagram below to answer each question.
1) If the pressure is normally 1.00 atm,
what is the normal freezing point of this
substance?
2) If the pressure is normally 1.00 atm,
what is the normal boiling point of this
substance?
3) What is the phase of a substance at
2.0 atm and 100 °C?
4) What is the phase of a substance at
0.75 atm and 100 °C?
5) What is the phase of a substance at
0.5 atm and 100 °C?
6) What is the phase of a substance at 1.5 atm and 50 °C?
7) What is the phase of a substance at 1.5 atm and 200 °C?
8) What is the phase of a substance at 1.5 atm and 800 °C?
9) What is the condition of the triple point of this substance? T= ________, P= _______
10) If I had a quantity of this substance at a pressure of 1.25 atm and a temperature of 3000C and lowered the pressure
to 0.25 atm, what phase change would happen?
11)If I had a quantity of this substance at a pressure of 0.75 atm and a temperature of -1000C, what phase change(s)
would occur if I increased the temperature to 6000C
12) If this substance was at a pressure of 2.0 atm, at what temperature would it melt?
13) If this substance was at a pressure of 2.0 atm, at what temperature would it boil?
14) If this substance was at a pressure of 0.75 atm, at what temperature would it melt?
15) If this substance was at a pressure of 0.75 atm, at what temperature would it boil?
16) If I had a quantity of this substance at a pressure of 1.00 atm and a temperature of -1000 C, what phase change(s)
would occur if I increased the temperature to 6000 C? At what temperature(s) would they occur? (NOTE: multiple
answers needed for this question)