# Determine Molar Mass of Gas from Ideal Gas Graph

We are required to calculate the relative molecular mass or molar mass of the gas using its graph of P against ^{1}/_{V}.

Let's take a look at the Ideal Gas Equation:

where:

P is pressure in Pa,

V is volume in m^{3},

n is moles of gas,

R is gas constant 8.31 J K^{-1} mol^{-1}, and

T is temperature in K.

We need to rearrange this equation in terms of P as the y-coordinate and ^{1}/_{V} as the x-coordinate.

Therefore nRT will be the gradient of this graph.

We can then calculate the gradient from data given in the question.

Next we can equate nRT to this gradient and solve for molar mass M.

Therefore the answer to this question is option B.

Topic: Gaseous State, Physical Chemistry, A Level Chemistry, Singapore

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