132 Lab Worksheet 6 (Ideal Gas Law) PDF

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Download 132 Lab Worksheet 6 (Ideal Gas Law) PDF

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Ideal Gas Law Problem-Solving What are the two types of Ideal Gas Law Problems? 1.

2.

What do you need to watch out for in plug-in problems?

How do you solve problems in which the gas undergoes a change in its pressure, volume, temperature, or number of moles during the problem (‘process’ problems)?

Ideal Gas Law Group Problem-Solving 1. A quantity of ideal gas in a rigid container in initially at room temperature (20C) and at a gauge pressure of 0.5 atm. If the gas is heated to a temperature of 60C, what will be the new value of the gauge pressure? a) Is this a ‘plug-in’ problem or a ‘process’ problem? __________________________ b) Solution

2. Show that 1.00 mol of ideal gas at a temperature of 0 °C and under a pressure of 1.0 atm occupies a volume of 22.4 liters. a) Is this a ‘plug-in’ problem or a ‘process’ problem? __________________________ b) Solution. Note that you can do this “show that” problem either by leaving the volume as an unknown and solving for it (showing that you get 0.0224 m3), OR by setting up the ideal gas law with a question mark over the equals sign, then plugging in values on each side, including 0.0224 m3 for the volume, showing the the two sides yield the same value. If you do the latter, remove the equals sign when you are down to a single number on each side, then put a check mark next to the equation to denote that you have shown the two sides are indeed equal.

3. A two mole sample of an ideal gas is contained in a leak-proof 5.0 liter container at 20 °C. The gas then undergoes an constant-pressure compression until the volume of the container is 3.0 liters. i) What is the final temperature of the gas sample (in °C)? ii) What is the final thermal energy of the gas sample? a) Is this a ‘plug-in’ problem or a ‘process’ problem? __________________________ b) Solution

4. An ideal gas is cooled at a constant volume until its pressure is one-fifth of the initial pressure. If the gas was initially at a temperature of 80 °C, what is its final temperature in °C? a) Is this a ‘plug-in’ problem or a ‘process’ problem? __________________________ b) Solution:

5. Four moles of an ideal gas are sealed in a hollow 0.04 m3 container and held at a pressure of 2.0 atm. What is the temperature of the gas in °C? a) Is this a ‘plug-in’ problem or a ‘process’ problem? __________________________ b) Solution:

Things to make sure come across: 1. 2. 3. 4. 5. 6.

Issue of gauge pressure Issue of units Issue of different R values (can do problem #2 both ways) Issue of when you need to convert and when you don’t How to approach a ratio type problem (by what factor will this change?) Converting square and cubic units (rather this not come up)...