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Heating Curves
Investigative Science
Notes
2 Lab book pages
• At A, T or KE increases and PE is constant.
• At B, the ice starts to melt at 0°C. T or KE is
constant and PE increases until all the ice is
melted.
• At C, T or KE increases and PE is constant.
• At D, the water starts to boil at 100°C. KE is
constant and PE increases until all the water
evaporated.
• At E, T or KE increases and PE is constant.
• At E, T or KE decreases and PE is constant.
• At D, the water vapor starts to condense. T or
KE is constant and PE decreases until all the
gas is condensed.
• At C, T or KE decreases and PE is constant.
• At B, the water starts to freeze at 0°C. T or KE is
constant and PE decreases until all the water is
frozen.
• At A, T or KE decreases and PE is constant.
A sample of water is heated from a liquid at 40oC to a gas
at 110oC.
a) On the heating curve diagram provided above, label
each of the following regions: Liquid, only ; Gas, only;
Phase change
b) For section QR of the graph, state what is happening to
the water molecules as heat is added.
c) For section RS of the graph, state what is happening to
the water molecules as heat is added.
The graph below represents the heating curve of a substance that starts as a
solid below its freezing point.
What is the melting point of this substance? (1) 30oC (2) 55oC (3) 90oC (4)
120oC