How many moles of methane, CH4, are present in 8.75 L at a pressure of 278.3 kPa and 843 K? (use R=

8.314 kPa•L•mol-1•K-1)

Part B. How many grams of CH4 are present in the sample above?

A. 0.347 mole

B. 5.55g

Explanation:

Data obtained from the question include the following:

Volume (V) = 8.75 L

Pressure (P) = 278.3 kPa

Temperature (T) = 843 K

Gas constant (R) = 8.314 kPa•L•mol-1•K-1

Number of mole (n) of CH4 =.?

Mass of CH4 = ?

A. Determination of the number of mole of CH4.

The number of mole of CH4 can be obtained by using the ideal gas equation as follow:

PV = nRT

Divide both side by RT

n = PV / RT

n = (278.3 x 8.75) / (8.314 x 843)

n = 0.347 mole

B. Determination of the mass of CH4.

The mass of CH4 can be obtained as follow:

Molar Mass of CH4 = 12 + (4x1) = 16g/mol

Number of mole CH4 = 0.347 mole

Mass of CH4 = ?

Mass = number of mole x molar Mass

Mass of CH4 = 0.347 x 16

Mass of CH4 = 5.55g