Problem : What is the density of carbon dioxide at 298 K and 1.0 atm?Use the equation for gas density:
|d = =|
Problem : 10 L of an unknown gas has a mass of 10.8 grams at a temperature of 310 K and 1.2 atm. What is the molar mass of the gas?Rearrange the gas density equation above to solve for μ :
Problem : A syringe of 0.010 mol O 2 and a syringe of 0.060 mol H 2 are forcibly injected into an evacuated glass jar of volume 1.0 L and temperature 273 K. What is the total pressure, and what are the partial pressures, of O 2 and H 2 ?
There are 0.010 + 0.060 = 0.070 mol of gas in the jar. Since we know volume and temperature, we can rearrange PV = nRT to find the total pressure. Using the value R = 0.0821 , we find that P tot = 1.6 atm.
To solve for the partial pressures of each gas, we use Charles' law. The mole fraction of O 2 is 0.010/0.070 = 0.14, so the partial pressure of O 2 is 14% of the total pressure, or 0.23 atm. Likewise, the mole fraction of H 2 is 0.060/0.070 = 0.86, so the partial pressure of H 2 is 1.4 atm.
Alternatively, you could have found the partial pressures directly and summed them to find the total pressure. Try both ways to see which works best for you.
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