Unit 9 Exam Review

Constants and Formulas

• Molar Volume : 22.4 L/mol• Ideal Gas Constant: .0821 L*atm/mol *K• Combined Gas Law: P1V1 = P2V2

• n1T1 n2T2

• Ideal Gas Law : PV = nRT• Dalton’s Law of Partial Pressure: Ptotal = P1 + P2+…Pn

Which of the following does not represent the behavior of an ideal

gas?1. A gas where the particles are far apart

3. A gas where the pressure is extremely high

2. A gas where the temperature is extremely low

4. A gas where the particles bounce off of one another

Which of the following describes the behavior of gases (in accordance with

KMT)?1. A larger gas particle has more KE than a smaller gas particle at the same temp

3. Gas particles bounce off of one another

4. Gases exert force on their containers

2. Gases slow down motion when temperature increases

Which formula will you need to solve the following:

A sample of air occupies 2.0 L in an engine cylinder has a given pressure. How many liters must the cylinder be compressed to make the pressure 4 times its original pressure?

•P1V1 = P2V2 or Boyle’s Law

Which formula will you need to solve the following:

A gas is heated so that it expands to three times it’s original size. How much does it need to be heated?

•V1/T1 = V2/T2 or Charles’ law

Which formula will you need to solve the following:

Calculate the new pressure of a sample of oxygen occupying 35 mL at STP that gets released into a 1.0 L flask held at 273 K.

•P1V1 = P2V2 or Boyle’s Law

Which formula will you need to solve the following:

A sample of carbon dioxide is trapped in a flask with sulfur dioxide. The flask is connected to a pressure sensor reading 140. kPa, and pressure of the sulfur dioxide is 60kPa. What is the pressure of the carbon dioxide?

•PTotal = P1(CO2) + P2(SO2) Dalton’s Law of Partial Pressures

Which formula will you need to solve the following:

How many degrees Celsius must a sample of ammonia gas in a rigid container be heated in order to double the pressure?

•P1/T1 = P2/T2 or Gay-Lussac’s law

Which formula will you need to solve the following:

If a sample of gas at 1.00 atm and 251 K gets compressed into a 50.0 mL container, causing the temperature to be 311 K and the pressure to be 1.50 atm, what was its original volume?

•P1V1 = P2V2 or Combined Gas Law (n is constant) n1T1 n2T2

Solve: If a sample of gas at 1.00 atm and 251 K gets compressed into a 50.0 mL container, causing the temperature to be 311 K and the pressure to be 1.50 atm, what was its original volume?

• 60.5 mL

Which formula will you need to solve the following:

How many moles of a gas occupy 400. mL at 760. mm Hg and 50.0 K?

•PV = nRT Ideal Gas Law

Solve: How many moles of a gas occupy 400. mL at 760. mm Hg and

50.0 K?

• .0974 mol

Oxygen gas at 35oC in a sealed, rigid container has a pressure of 2.40 atm. If it is cooled to 5oC, what will the new pressure be?

•2.17 atm (rigid container = constant volume; sealed = constant mole)

2 NaHCO3(s) 1 Na2CO3(s) + 1 H2O(g) + 1 CO2 (g)

If 6.00 moles of NaHCO3 react as shown above, how many liters of CO2 gas will be produced at STP?

•Convert mol NaHCO3 to mol CO2

•Use molar volume because it’s at STP to convert to mol CO2

•67.2 L

The syringe volume was increased from 2.07 mL to 6.13 mL. If the original pressure was 1209 torr, what is the pressure when expanded?

•408 torr

If a sample of ammonia gas at STP has a volume of 12.1 L, what will its volume be when heated to 273.0oC at constant pressure?

•24.2 L

If a gas in a rigid container has a pressure of 2.05 atm when the temperature is 310. K, what temperature does it need to be heated to in order to reach 4.01 atm of pressure?

•606 K

What will happen to the pressure of a gas at a constant temperature if its volume is decreased from 3.0 L to 1.0 L ?

•The pressure will triple

Which of these identical cylinders is under the greatest pressure?

A B C D 1.00 mol 1.00 mol 0.5 mol 0.5 mol 250 K 300 K 250 K 300 K

•B (most mol with the highest temp)

Which of these identical cylinders is under the greatest pressure?

A B C D 2.0 mol 1.0 mol 0.5 mol 0.5 mol 250 K 300 K 500 K 600 K

•A (most amount of moles/particles of gas)