Phase Change Worksheet Key
Part 1:
Label the diagram below with the following terms: Solid, Liquid, Gas, Vaporization, Condensation, Freezing, Melting
Part 2:
The graph was drawn from data collected as a substance was heated at a constant rate. Use the graph and the words in the
word bank to complete the statement.
At point A, the beginning of observations, the
substance exists in a solid state. Material in this phase
has definite volume and shape. With each passing
minute energy is added to the substance. This causes
the molecules of the solid substance to vibrate more
rapidly which we detect by a rise in temperature of the
substance. At point B, the temperature of the substance
is 70°C. The solid begins to melt. At point C, the
substance is completely melted or in a liquid state.
Material in this phase has indefinite shape and definite
volume. The energy put to the substance between
minutes 5 and 9 was used to convert the substance
from a solid to a liquid. This heat energy is called the
heat of fusion.
Between 9 and 13 minutes, the added energy increases the temperature of the substance. During the time from
point D to point E, the liquid is vaporizing. By point E, the substance is completely in the gas phase. Material in
this phase has indefinite volume and shape. The energy put to the substance between minutes 13 and 18 converted
the substance from a liquid to a gas state. This heat energy is called the heat of vaporization. Beyond point E, the
substance is still in the gas phase, but the molecules are moving faster as indicated by the increasing temperature.
Liquid
Indefinite
Solid
Volume
Definite
Faster
Shape
Vaporizing
Melt
Rise
Vibrate
Energy
70
Temperature
Gas
Condensation
Vaporization
Melting
Liquid
Solid
Gas
Freezing
