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Charles’ Law. Temperature Changes & Matter. Solids & Liquids expand and contract as temperature changes. Change is usually very small Gases show large volume changes with temperature changes. Jacques Charles. Balloonist - PowerPoint PPT Presentation
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Charles’ Law
Temperature Changes & MatterTemperature Changes & Matter
Solids & Liquids expand and contract as Solids & Liquids expand and contract as temperature changes. temperature changes. – Change is usually very smallChange is usually very small
Gases show large volume changes with Gases show large volume changes with temperature changestemperature changes
Jacques CharlesJacques Charles
Balloonist
1787 did experiments showing how volume of gases depends on temperature
How do hot air balloons work?How do hot air balloons work?
Relationship between V and TRelationship between V and TPressure & amount are constant
At high temperature, the gas particles move faster and collide with the walls more often
Pressure is constant, so volume has to increase
Data for Volume-TemperatureData for Volume-Temperature
20220230030055
16716720020044
13213210010033
114114505022
100100101011
Volume (mL)Volume (mL)Temperature (Temperature (C)C)TrialTrial
What did Charles do next?What did Charles do next?
0
5 0
1 0 0
1 5 0
2 0 0
2 5 0
0 50 100 150 200 250 300 350
10
50
100
200
300
Linear RelationshipLinear Relationship
Plot Volume vs Plot Volume vs CC and you get a straight and you get a straight line line
The relationship between Volume and The relationship between Volume and C C is is linearlinear
0
5 0
1 0 0
1 5 0
2 0 0
2 5 0
0 100 200 300 400 500 600 700
283
323
373
473
573
Charles extrapolated the graph to 0 volume.At 0 mL, the X-intercept is -273 C
Hints of Kelvin scaleHints of Kelvin scale
Charles extrapolated his data to see the Charles extrapolated his data to see the temperature at which the volume was 0temperature at which the volume was 0
This was the first indication that the This was the first indication that the temperature -273 temperature -273 C might have a C might have a fundamental meaningfundamental meaning
Why did Charles have to extrapolate his lines Why did Charles have to extrapolate his lines in this temperature range instead of taking in this temperature range instead of taking data?data?
Plot Volume vs. Kelvin Temp.Plot Volume vs. Kelvin Temp.
Get a straight line that passes through the Get a straight line that passes through the originorigin
The relationship between the variables is The relationship between the variables is directdirect
Charles’ Law:Charles’ Law: Verbal Verbal
The volume of a gas The volume of a gas
at constant pressure at constant pressure
varies directly with varies directly with
its absolute temperatureits absolute temperature
Charles’ Law: Charles’ Law: Graphically Graphically
Plot V vs Kelvin TemperaturePlot V vs Kelvin Temperature
Straight line that passes through the origin Straight line that passes through the origin
V = kT or V = kT or VV = k = kT
Charles’ Law:Charles’ Law: Problems Problems
VV11 = = VV22
T1 T2
Given any 3 variables, you can find the 4th
Problem 1Problem 1
150 mL of a gas at constant pressure150 mL of a gas at constant pressureTemperature increases from 20Temperature increases from 20C to 40C to 40CCWhat is the new volume?What is the new volume?
Step 1:Step 1: Convert T Convert T11 and T and T22 to Kelvin scale. to Kelvin scale.
Step 2:Step 2: Rearrange equation: Rearrange equation:
VV11 = = VV22 becomes becomes VV11TT22 = V = V22
TT11 T T22 T T11
Step 3:Step 3: Substitute and solve: Substitute and solve: 150 mL X 313 K150 mL X 313 K 293 K293 K
= 160 mL
The low temperature region is always extrapolated. Why?
Balloons can expand & contract with the gasBalloons can expand & contract with the gashttp://www.youtube.com/watch?v=IkRIKGN3i0k