The partial pressure of CH 4 ( g ) is 0.175 atm and that of O 2 ( g ) is 0.250 atm in a mixture of the two gases. a. What is the mole fraction of each gas in the mixture? b. If the mixture occupies a volume of 10.5 L at 65°C, calculate the total number of moles of gas in the mixture. c. Calculate the number of grams of each gas in the mixture.

Interpretation: The total number of moles in the mixture, the mole fractions and the number of grams of each gas in the given mixture is needed to be determined if the partial pressure of CH4 is 0.175 atm and O2 is 0.250 atm .

Concept introduction:

• Partial pressure of a gas in a mixture of gases is the pressure of that gas when it alone.

  Partial pressure of a gas in terms of its mole fraction and total pressure is,

  ` PA  =  χA  ×  PTOTAL

• A mole fraction of a molecule in a mixture is the ratio of number of moles of particular molecule to the sum of number of moles of all molecules in the mixture.

• The number of moles of molecule can be find out by using its mole fraction,

• numbers  of moles of molecule A (nA)   =   molecule  fraction  of A, ( χA) × total number of moles

• Number of grams of a substance from its number of moles is,

Number of moles  ×  Molecular mass in grams  =   Number of grams

• Total number of moles of gases in the mixture of gases can be determined by using ideal gas equation.

According to ideal gas equation,

Total number of moles    =    Total pressure  ×  Volume R  ×  Temperature    

To determine: the total number of moles in the mixture, the mole fractions and the number of grams of each gas in the given mixture.

To find: the mole fractions of CH4 and O2 in the given mixture if the partial pressure of CH4 is 0.175 atm and O2 is 0.250 atm .

Mole fraction of CH4 is 0.412 .

Mole fraction of O2 is 0.588 .

The partial pressure of CH4 is given as 0.175 atm

The partial pressure of O2 is given as 0.250 atm .

Therefore, the total pressure of the mixture is,

0.175 atm  +  0.250 atm  =  0.425 atm

Equation for finding mole fraction from partial pressure and total pressure is,

χA  =   PAPTOTAL    

Therefore

Interpretation: The total number of moles in the mixture, the mole fractions and the number of grams of each gas in the given mixture is needed to be determined if the partial pressure of CH4 is 0.175 atm and O2 is 0.250 atm .

Concept introduction:

• Partial pressure of a gas in a mixture of gases is the pressure of that gas when it alone.

  Partial pressure of a gas in terms of its mole fraction and total pressure is,

  ` PA  =  χA  ×  PTOTAL

• A mole fraction of a molecule in a mixture is the ratio of number of moles of particular molecule to the sum of number of moles of all molecules in the mixture.

• The number of moles of molecule can be find out by using its mole fraction,

• numbers  of moles of molecule A (nA)   =   molecule  fraction  of A, ( χA) × total number of moles

• Number of grams of a substance from its number of moles is,

Number of moles  ×  Molecular mass in grams  =   Number of grams

• Total number of moles of gases in the mixture of gases can be determined by using ideal gas equation.

According to ideal gas equation,

Total number of moles    =    Total pressure  ×  Volume R  ×  Temperature    

To determine: the total number of moles in the mixture, the mole fractions and the number of grams of each gas in the given mixture.

Interpretation: The total number of moles in the mixture, the mole fractions and the number of grams of each gas in the given mixture is needed to be determined if the partial pressure of CH4 is 0.175 atm and O2 is 0.250 atm .

Concept introduction:

• Partial pressure of a gas in a mixture of gases is the pressure of that gas when it alone.

  Partial pressure of a gas in terms of its mole fraction and total pressure is,

  ` PA  =  χA  ×  PTOTAL

• A mole fraction of a molecule in a mixture is the ratio of number of moles of particular molecule to the sum of number of moles of all molecules in the mixture.

• The number of moles of molecule can be find out by using its mole fraction,

• numbers  of moles of molecule A (nA)   =   molecule  fraction  of A, ( χA) × total number of moles

• Number of grams of a substance from its number of moles is,

Number of moles  ×  Molecular mass in grams  =   Number of grams

• Total number of moles of gases in the mixture of gases can be determined by using ideal gas equation.

According to ideal gas equation,

Total number of moles    =    Total pressure  ×  Volume R  ×  Temperature    

To determine: the total number of moles in the mixture, the mole fractions and the number of grams of each gas in the given mixture.