Question

PART A:

Three gases (8.00 g of methane, C H 4 , 18.0 g of ethane, C 2 H 6 , and an unknown amount of propane, C 3 H 8 ) were added to the same 10.0- L container. At 23.0 ∘ C , the total pressure in the container is 3.80 atm . Calculate the partial pressure of each gas in the container. Express the pressure values numerically in atmospheres, separated by commas. Enter the partial pressure of methane first, then ethane, then propane.

PART B:

A gaseous mixture of O2 and N2 contains 30.8 % nitrogen by mass. What is the partial pressure of oxygen in the mixture if the total pressure is 665 mmHg ?

Express you answer numerically in millimeters of mercury.

Answer 1

PART A The total number of moles of gases present in the 10.0-L container is calculated by the following formula PV nRT PV RT n is the number of moles, R is gas constant Here, P is the pressure, V is the volume, -atm K1 mol1), and T is the temperature (0.0821L Conversion of units of temperature from Kelvin to degree Celsius is done by the following formula T(K) T(°C)+273 K Substitute the given temperature, 23°C in the above formula as shown below: T(K) 23+273.15K 296.15 K _ Substitute the values of pressure, volume, gas constant and temperature in the above formula as shown below: PV RT 3.80 atm x10.0 L 0.0821L atm K mol7x296.15 K =1.56mol The total number of moles of gases present in the 10.0-L container is 1.56 mol The number of moles of methane and ethane is calculated as shown below: Given mass Number of moles Molar mass 8.0 Number of moles of methane 16.0 g/mol =0.5mol

18.0 Number of moles of ethane 30.0 g/mol 0.6mol shown below The number of moles of propane is calculated as Number of moles of methane +Number of moles of ethane Total number of moles = +Number of moles of propane 1.56mol 0.5 mol +0.6 mol + Number of moles of propane Number of moles of propane 0.46m ol The Mole fraction of propane is calculated as shown below: Moles of propane Mole fraction of propane = Total moles 0.46 moles 1.56moles =0.295 shown below The partial pressure of propane is calculated as Partial pressure of propane= moles fraction of propane xtotal pressure =0.295x3.80atm 1.121 atm The partial pressure of methane is calculated as shown below Partial pressure of methane=moles fraction of methanex total pressure 0.5mol3.80 atm 1.56mol 1.218 atm The partial pressure of ethane is calculated as shown below: Partial pressure of ethane-moles fraction of ethanex total pres sure X 0.6mol x 3.80atm 1.56mol 1.462 atm

The partial pressure of methane, ethane, propane is 1.121 atm, 1.218 atm, 1.462 atm respectively PART B contains 30.8 % nitrogen by mass. For 100 g sample A gaseous mixture of O2 and N 30.8 g is of N1 gas and remaining 100g-30.8g 69.2g is O2 gas. The number of moles of O2 and N, is calculated as shown below S Given mass Number of moles = Molar mass 69.2 Number of moles of O2 32 g/mol - 2.1625 mol 30.8 Number of moles of N _ 28 g/mol =1.1mol The total number of moles is 2.1625mol +1.lmol = 3.2625 mol The partial pressure of O2 is calculated as shown below: Partial pressure of O2 moles fraction of O2 x total pres sure 2.1625 x665 mm Hg 3.2625 440,81 mm Hg = The partial pressure of O2 is440.81 Hg mm