# Note : You must memorize STP and the gas laws!! - PowerPoint PPT Presentation

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Note : You must memorize STP and the gas laws!!.

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Note : You must memorize STP and the gas laws!!

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## Note: You must memorize STP and the gas laws!!

The Kinetic Molecular Theory states that gas particles are ____________ and are separated from one another by lots of _________ space. Particles are in constant, rapid and _________ motion. The particles collide with each other and the sides of the container – this is what causes ______________. During these collisions, no ___________ is lost. The higher the _______________, the faster the particles move.

small

empty

random

Pressure

energy

temperature

• List 4 properties of gases.

• 1.

• 2.

• 3.

• 4.

Low Density

Conform to container size

Can diffuse & effuse

Can be compressed

Explain why gases are compressible, have a low density and can diffuse:

Compressible, because of lg amount of empty space

Low density, due to lots of empty space

Diffuse, due to random, rapid particle motion

vacuum

air pressure

HG

HG

4. A _______________ is used to measure atmospheric pressure. Draw a picture of one and know how it works.

barometer

5. What 4 variables are used to describe gases? What units do we use for these variables?

1.

2.

3.

4.

Pressure - atm

Volume - L

Amount of gas - moles

Temperature - k

6. When pressure doubles on a fixed sample of gas and the temperature remains constant, what will happen to the volume? _______________________ (be specific)

Reduce by 1/2

7. When the temperature of a fixed sample of gas triples and the pressure remains constant, what happens to the volume? _______________________ (be specific)

Volume triples

8. If the pressure on a fixed amount of gas in a rigid container is reduced by half, what had to happen to the temperature of that gas? _______________________ (be specific)

decreases by 1/2

9. State Dalton’s law of partial pressures in words & write the equation.

Total pressure of gas sample is equal to the sum of all gases in the sample ( pt = p1 + p2 + p3…)

• What does STP stand for?

11. Standard temperature is ________ C or _________ K.

12. Standard pressure is _________ atm, __________ kPa or _________ mm Hg.

Standard Temperature Pressure

0

273

1 atm

101.3

760

14. One mole of any gas at STP occupies _________ L. This is called the ___________ volume.

1 Mol of gas at STP is 22.4L.

22.4

molar

15. Write the equation for the combined gas law.

16. Write the equation for the ideal gas law. Know what all the variables represent!

P1V1 / T1 = P2V2 / T2

PV = nRT

17. When solving gas law problems, temperature must always be expressed in _____________.

Kelvin

18. When using the ideal gas law (and only this law), volume must be in units of __________

temperature must be in _____________

pressure must be in ________________

“n” must be in ____________________

L

K

atm

mol

19. When pressure is expressed in atm the value for the ideal gas law constant R = ___________. * I’ll give you these on the test!

.0821

1. At 100.0 kPa a balloon has a volume of 1.50 L. What will the volume be at a pressure of 3.25 atm?

2. A 1.25 L container holds 17.5 g oxygen gas (O2) of gas at 275 K. What is the pressure?

3. A balloon as a volume of 15.4 L at STP. What would its volume be at 1.25 atm when the temperature decreases 55K?

4. A gas is generated at 20.0 C and 2.100 atm. Under a constant volume, the gas is heated to a pressure of 3.13 atm. What is the new temperature?

5. If a gas has a volume of 25.5 L at a temperature of 95.0C, what is the temperature if the volume is decreased to 5.0 L?

6. If 2.65 mole of methane gas occupy 15.0 L at 1.50 atm, what is the temperature of the gas in K? and in Celsius?

7. A gas is collected by water displacement. If the total pressure is 103.67 kPa at and the pressure due to the water vapor is 1.72 kPa, what is the pressure of the dry gas?

8. What is the mass of 14.50 L of oxygen gas at STP?

9. How many grams of hydrogen gas are needed to react with 25.50 L of oxygen gas at 2.50 atm and 23.95C.

2 H2 + O2  2 H2O

3. How many liters of carbon monoxide are needed to react with 4.85 g of oxygen gas to produce carbon dioxide? DCO = .0958 g/L. Equation: