10.3 – phase change lab KEY

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Solid
Liquid
Gas
Can’t change shape or volume
Can change shape not volume
Can change shape and volume
freezing
-liquid to solid
melting
-solid to liquid
condensation -gas to liquid
vaporization/boiling
sublimation
-liquid to gas
-solid to gas
Temperature measures the Kinetic Energy (speed) of the
particles in a substance.
As you add heat to a substance the particles will
move faster.
o
Water boils at 100 C and ice water exists at
o
0 C.
Heating Curve of Water
o
Temperature ( C) --> 1 square = 5 C
Hold paper sideways, holes on top
Time (s) --> 1 square = 30 seconds
O
Heating Curve of Water
120
100
80
60
Water Temp (degrees Celcius)
40
20
0
0:00
-20
1:12
2:24
3:36
4:48
6:00
7:12
8:24
9:36
10:48
12:00
Sources of error could be calibration of
thermometer, purity of the water, the placement
of the thermometer, how you stirred,.
Water can boil at temps greater than
O
100 C if there are impurities in the water.
Another possibility is a miscalibrated
thermometer
(When ice melts or water boils)
The temperature of a substance going
through a phase change will remain
constant.
(When there was only water!)
The temperature increased when
there was only one phase present in
the beaker.
While the ice is melting, the energy
is weakening the intermolecular
forces causing a phase change.
When only water is in the beaker,
the energy speeds up the water
molecules, which increases
temperature. When the water is
boiling the energy is weakening the
intermolecular forces causing a
phase change.
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