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MiSP Phase Changes Worksheet #3 L ASSESSMENT
Name _____________________________ Date_____________ L 1, 2, 3 Introduction: The graph below was drawn from data collected as a substance was heated at a constant rate. Use the graph and word bank to answer the following questions. –
At point A , the beginning of observations, the substance exists in a solid state. Material in this phase has a definite volume and definite shape. With each passing minute, _____________ is added to the substance. This causes the molecules of the substance to ____________ more rapidly which we detect by an increase in the ______________ of the substance. At point B , the temperature of the substance is ______°C. The solid begins
Word bank: Some words may be used more than once. Some not at all. gas solid faster cool boiling slower heat temperature melted freezing liquid move melt condensing
to __________. At point C, the substance is completely ____________ or in a ___________ state. Material in this phase has a definite volume and does not have a definite shape. The energy put into the substance between minutes 5 and 9 was used to convert the substance from a ___________ to a ___________.
Between 9 and 13 minutes, the added energy increases the ______________ of the substance. During the time from point D to point E , the liquid is ___________. By point E , the substance is completely in the __________ phase. Material in this phase does not have a definite volume or a definite shape. The energy put into the substance between minutes 13 and 18 converted the substance from a ___________ to a ___________ state. Beyond point E , the substance is still in the ______________ phase, but the molecules are moving _______________ as indicated by the increasing temperature.
Which of these three substances was likely used in this phase change experiment?
L2,
1a. The unit rate of change (slope) of each of the lines between points B + C and D + E is 0 (zero). That tells us that in those two lines, as time passes, the temperature _________________________________.
Substance Meltingpoint Boiling point Bolognium 20 °C 100 °C Unobtainium 40 °C 140 °C Foosium 70 °C 140 °C
The data was graphed:
Heating/Melting of Tetangtoe
0
10
20
30
40
50
60
0 5 10 15 20 Tim e (m inutes)
Temperature degrees C
- Determined the y intercept and unit rate of change (slope) for the line between 0 and 4 minutes. y intercept
Unit rate of change (slope)
- Determine the formula for the line between 0 and 4 minutes using the y intercept and slope calculated in 3 above.
- Using the formula for the line between 0 and 4 minutes from question #4, What will the temperature be after 3.25 minutes? Show work.
- Why would you not use the formula from #4 above to calculate the temperature at 15 minutes?
