Gasoline (petrol)

3 marks · Normal

A household gas tank contains 18 kg of liquefied petroleum gas (LPG), which is a typical use of refinery gases. LPG is mainly a mixture of propane () and butane ().

If the average molar mass of LPG is assumed to be , calculate how many moles of LPG the tank contains. State one typical domestic use of LPG in your answer.

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

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(a) 400 mol; example use: domestic heating OR cooking mol · must show correct method for mole calculation, valid typical use stated

Also accept: calculation with propane or butane average molar mass

Common mistakes: incorrect conversion of kg to g; not giving a typical use

Show mark scheme and worked solution

Marking points

M1 · 1 mark · Convert 18 kg to g OR state correct formula for moles.

M2 · 1 mark · Divide mass by molar mass to find moles.

I1 · 1 mark · State a typical domestic use of LPG (e.g. heating or cooking).

Worked solution

Step 1: Convert mass from kg to g.

Step 2: Use the formula:

Step 3: A typical use of LPG (refinery gases) is for domestic heating or cooking.