Unit 6: Lesson 3 - Gas Laws

Unit 6: Lesson 3 - Gas Laws

By Liela Abouzeenni

Multiple Choice

First things first, on Monday when we come back to school (note there are no correct answers, I just chose one so I can get different colours for your answers) do you plan to come back to school or stay home?

• Come back to school

• Continue online at home

Absolute Zero and the Temp. Scale

• Scientists graphed the volume of gases to temperature and noticed a pattern.

• They extended the data lines to meet at one point.

• This theoretical temperature represents absolute zero, where all gases have zero volume and its the lowest possible temperature. ​

Celsius scale sets freezing point of water at 0^oC and boiling point at 100^oC.

There are 100 notches between the 2 values, or 100 degrees.

Celsius is also called centigrade scale. ​

​Kelvins uses the same scale, but resets the starting point at absolute zero.

0K = -273^oC = absolute zero​

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​Celsius vs Kelvins

Some Formulas NEED a Specific Unit

I won't bore you, I'm sure you can do it on your own.

I won't bore you, I'm sure you can do it on your own.

Multiple Choice

Convert -78^oC to absolute temperature (K).

• 78K

• 195K

• 273K

• 351K

Multiple Choice

Convert 45^oC to absolute temperature (K).

• -228K

• 351K

• 318K

• 65K

Multiple Choice

Convert 1337K to the centigrade scale (^oC).

• 1064^oC

• 1610^oC

• 5x10^4oC

• 1.111x10^3oC

Multiple Choice

Convert 210K to the centigrade scale (^oC).

• 64^oC

• -63^oC

• -100^oC

• -273^oC

Multiple Choice

A sample of methane gas occupies an initial volume of 5.25 L at an initial temperature of 200 K. The gas is heated to 300 K while the pressure and the amount of gas remain constant. Determine the new volume.

• 22.3L

• 10.5L

• 7.5L

• 7.88L

Multiple Choice

A sample of carbon dioxide is placed in a piston. The initial temperature of the gas is 35 °C and it occupies a volume of 2.2 L. Calculate the temperature at which it will occupy 4.4 L. Pressure and the amount of gas remain constant.

• 620K

• 320K

• 273k

• 750K

Boyle first noticed that volume decreases with added pressure.

By graphing the inverse pressure (1/P) to the volume he was able to find a linear relationship between the 2.

He observed that they are inversely proportionate to each other.

By graphing pressure versus volume he was able to find a linear relationship between the 2.

He observed that they are directly proportionate to each other.

Multiple Choice

Helium gas has a volume of 8.25 L at 446 kPa. What pressure must be applied to the gas when it occupies 12 L?

• 703kPa

• 275kPa

• 307kPa

• 223kPa

Multiple Choice

A 1.75 L sample of ammonia gas increases in volume to 6.50 L when the pressure reaches 2.84 kPa. What was the original pressure of this gas?

• 10.5kPa

• 2.84kPa

• 6.75kPa

• 1.50kPa

Multiple Choice

Soccer balls are typically inflated to between 60 and 110 kPa. A soccer ball is inflated indoors with a pressure of 85 kPa at 25 °C. If it is taken outside, where the temperature on the playing field is -11.4 °C, what is the pressure of the gas inside the soccer ball?

• 25kPa

• 110kPa

• 87.3kPa

• 75kPa

​The Combined Gas Law

​

is a combination of the 3 gas laws.

Each law is a special case of the combined gas law. ​

Multiple Choice

A balloon at the top of Mount Logan occupies a volume (V1) of 775 mL at a temperature of -28 °C (T1) and a pressure of 92.5 kPa (P1). What is the pressure (P2) at the bottom of the mountain if the same balloon has a volume (V2) of 825 mL at a temperature (T2) of 15 °C?

• 102kPa

• 202kPa

• 132kPa

• 99kPa

Multiple Choice

A researcher heated a 2.75 L sample of helium gas at 99.0 kPa from 21.0 °C to 71.0°C, and recorded that the pressure changed to 105 kPa. Calculate the final volume of the gas.

• 4.38L

• 6.06L

• 8.77L

• 3.03L

Multiple Choice

A 450 mL sample of propane gas at 253 kPa and 15 °C was compressed to 310 mL at a pressure of 405 kPa. Calculate the final temperature in Celsius.

• 25^oC

• 45^oC

• 30^oC

• 60^oC

Practice Problems

​You can work with a partner

Chapter 11.8

pg ​553 #1, 4, 5, 6

Chapter 11.9

pg ​562 #​2-8

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