The Gas Laws. Using temperature, pressure, and volume, there are 3 basic gas laws: Boyle’s,...
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Transcript of The Gas Laws. Using temperature, pressure, and volume, there are 3 basic gas laws: Boyle’s,...
11.2 NOTESThe Gas Laws
11.2
Using temperature, pressure, and volume, there are 3 basic gas laws: Boyle’s, Charles’s, and Gay-Lussac’s
11.2
Boyle’s Law
11.2
Boyle’s Law
If the temperature is kept constant, the pressure and volume are inversely proportional.P. 369
11.2
Boyle’s Law
If the temperature is kept constant, the pressure and volume are inversely proportional.P. 369 and 370
PV = kk is a constant and is the same no matter what gas, as long as the temperature and the amount of gas stay the same.
11.2
Boyle’s Law
If the temperature is kept constant, the pressure and volume are inversely proportional.
PV = kSince the pressure times the volume always equals the
same constant, even if the pressure or the volume is changed (as long as the temperature and amount of gas is constant) the new PV will equal the original PV
P1V1 = P2V2
11.2
Example 1: 1.00L of a gas at standard temperature and pressure is compressed to 473mL. What is the new pressure of the gas?
11.2
Example 2: The highest pressure ever produced in a laboratory setting was about 2.0 x 106 atm. If we have a 1.0 x 10-5 L sample of a gas, at that pressure, then release the pressure until it is equal to 0.275 atm, what would be the new volume of that gas?
11.2
Charles’s Law
11.2
Charles’s Law
If the pressure and amount of gas are kept constant, the volume and the temperature are directly proportional.
p. 371 and 372The temperature has to be in Kelvin. Why?
11.2
Charles’s Law
If the pressure and amount of gas are kept constant, the volume and the temperature are directly proportional.
The temperature has to be in Kelvin.0ºC = 273 K
To change from Celsius to Kelvin, add 273.To change from Kelvin to Celsius, subtract 273.
11.2
Charles’s Law
If the pressure and amount of gas are kept constant, the volume and the temperature are directly proportional.
V/T = k
V1 / T1 = V2 / T2
11.2
Example 3: On hot days you may have noticed that potato chip bags seem to inflate, even though they have not been opened. If I have a 250 mL bag at a temperature of 19ºC, and I leave it in my car which has a temperature of 60ºC, does the bag expand? To what size?
11.2
Example 4: A soda bottle is flexible enough that the volume of the bottle can change even without opening it. If you have an empty soda bottle (volume 2.0 L) at room temperature (25ºC), what will the new volume be if you put it in your freezer (-4ºC)?
11.2
Gay-Lussac’s Law
11.2
Gay-Lussac’s Law
If the volume and amount of gas are kept constant, the pressure and temperature are directly proportional.
p. 373P/T = kP1 / T1 = P2 / T2
11.2
Example 5: A gas has a pressure of 699.0 mmHg at 40ºC. What is the temperature at standard pressure, if the volume is kept constant?
11.2
Example 6: Calculate the final pressure inside a scuba tank after it cools from 1.00 x 103 ºC to 25ºC. The initial pressure in the tank is 130 atm.
11.2
Combined Gas Law
Boyle’s, Charles’s, and Gay-Lussac’s can be combined into one law.
P1 V1 = P2 V2
T1 T2
11.2
Example 7: What is the volume at STP of 720 mL of a gas collected at 20 ºC and 3 atm?
11.2
Example 8: 690 mL of oxygen are collected over water at 26 ºC and a total pressure of 725 mmHg. What is the volume of the dry oxygen at 52 ºC and 800 mmHg?
11.2 Practice Problems
p.367 #1 (You will need table on p. 859)
p. 370 #1 p. 372 #1 and 2 p. 374 #1, 2, and 3 p. 375 #1 and 2