Determine Molar Mass of Gas from Ideal Gas Graph

det molar mass of gas from ideal gas graph question

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:

det molar mass of gas from ideal gas graph equation

where:
P is pressure in Pa,
V is volume in m3,
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.

det molar mass of gas from ideal gas graph p against 1 over v

Therefore nRT will be the gradient of this graph.

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

det molar mass of gas from ideal gas graph calculate gradient

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

det molar mass of gas from ideal gas graph calculate molar mass

Therefore the answer to this question is option B.

det molar mass of gas from ideal gas graph answer

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

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