The **Van der Waals Equation** is used when dealing with real, non-ideal gases.

Concept #1: Van der Waals Equation

The **Van der Waals Equation **takes into consideration that real gases do not behave ideally. As a result these gases can experience attractive or repulsive forces while also having definite volumes.

Example #1: Van der Waals Equation

Example #2: Van der Waals Equation

Example #3: Van der Waals Equation

Example #4: Van der Waals Equation

Use the van der Waals equation and the ideal gas equation to calculate the pressure exerted by 1.000 mol of Cl2 in a volume of 5.000 L. at a temperature of 273.0 K. Explain why the two values are different.

Which gas molecule do you expect to be the largest? (a and b are Van der Waals constants.)
1. Butane
2. Acetonitrile
3. Freon

Use the van der Waal's equation to calculate the pressure (in atm) exerted by 1.00 mol of chlorine gas confined to a volume of 2.00 L at 273K. The value of a = 6.49 L2 atm mol-2, and that of b = 0.0562 L mol-1 for chlorine gas.
a) no given answer is close
b) 9.9
c) 4.12
d) 1.54
e) 3.73

Which gas would you expect to have the largest value for the van der Waals constant “a”?
1. Ne
2. CH4
3. He
4. NH3

The constant a in the Van der Waal’s equation corrects for ________and is important at ________.
a. intermolecular attraction, high temperature
b. intermolecular attraction, low temperature
c. lower than average energy of molecules, low temperature
d. volume of molecules, low pressure
e. volume of molecules, high pressure

Use the van der Waals equation of state to calculate the pressure of 2.70 mol of Xe at 473 K in a 5.50-L vessel. Van der Waals constants can be found below.
P= ______________ atm
Use the ideal gas equation to calculate the pressure under the same conditions.
P=_______________atm

Calculate the pressure in bar of 8.5 mol of ethanol vapor in a 12.0-L container held at 82°C:a. treating ethanol vapor as a van der Waal's gas,b. treating ethanol as an ideal gas.

At high pressures, real gases do not behave ideally. (a) Use the van der Waals equation and data in the text to calculate the pressure exerted by 10.5 g _2 at 20 C in a 1.00 L container. (b) Repeat the calculation assuming that the gas behaves like an ideal gas. van der Waals (real) gas pressure ideal gas pressure

Calculate the pressure that CCl4 will exert at 43 C if 1.20 mol occupies 33.5 L, assuming that CCl4 obeys the ideal-gas equation: P = CCl4 obeys the van der Waals equation. (Values for the van der Waals constants are a = 20.4, b = 0.1383.)

Use the van der Waals equation to calculate the pressure exerted by 1.330 mol of Cl_2 in a volume of 5.285 L at a temperature of 303.0 K. Use the ideal gas equation to calculate the pressure exerted by 1.330 mol of Cl_2 in a volume of 5.285 L at a temperature of 303.0 K.

Use the van der Waals equation of state to calculate the pressure of 2.80 mol of NH3 at 483 K in a 5.50 L vessel.Use the ideal gas equation to calculate the pressure under the same conditions.

Use the van der Waals equation of state to calculate the pressure of 2.20 mol of Xe at 497 K in a 4.40 L vessel. Van der Waals constants can be found here. Use the ideal gas equation to calculate the pressure under the same conditions.

Use the van der Waals equation of state to calculate the pressure of 2.50 mol of H2O at 497 K in a 4.90 L vessel. Van der Waals constants can be found here. Use the ideal gas equation to calculate the pressure under the same conditions.

According to the ideal gas law, a 9.847 mol sample of methane gas in a 0.8237 L container at 500.0 K should exert a pressure of 490.5 atm. By what percent does the pressure calculated using the van der Waals' equation differ from the ideal pressure? For CH4 gas, a = 2.253 L2 atm/mol2 and b = 4.278 x 10-2 L/mol.

15.0 moles of gas are in a 8.00 L tank at 22.2°C. Calculate the difference in pressure between methane and an ideal gas under these conditions. The van der Waals constants for methane are a = 2.300 L2 • atm/mol2 and b = 0.0430 L/mol. Express your answer with the appropriate units.

At high pressures, real gases do not behave ideally. (a) Use the van der Waals equation and data in the text to calculate the pressure exerted by 21.0 g H2 at 20°C in a 1.00 L container. (b) Repeat the calculation assuming that the gas behaves like an ideal gas.