Chemistry - Using the ideal gas equation-mole exercises(2)

Solution

Step 1- Find the pressure the gas exerts.

Step 2- Convert the temperature from Celsius to Kelvin.

Step 3- Convert the volume from millilitres to litres.

Step 4- Solve for the numb er of mole

Click on each step for extra assistance

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The pressure of the gas is 740mmHg. We must convert the pressure from mmHg to kilopascals.
760mmHg = 101.3kPa
So

740mmHg = (740/760) X 101.3 = 98.63 kPa

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27 degrees Celsius is (273 + 27) 300^o K

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The volume is already given in litres
12.5 litres.

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Place the values of each variable in the formula and solve for the number of mole of methane

n = (98.63 X 12.5) / (8.31 X 300) = 0.495 mole of methane

Mole of oxygen = 3 X mole of methane
=> 3 X 0.495 = 1.48

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The ideal gas equation

(2)

A chemist wishes to react all the methane in a 12.5 litre cylinder with oxygen. The pressure gauge on the cylinder reads 740mmHg and the temperature is 27^oC. Methane reacts with oxygen according to the equation below.
CH₄ + 3O₂ => CO₂ + 2H₂O.
The chemist knows that for every mole of methane she needs 3 mole of oxygen for complete reaction.

What is the number of moles of oxygen gas required?

(Atomic mass of N= 14)
Clues

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