As fuels
3 marks · NormalA certain crude oil contains 1000 kg of hydrocarbons. When it is separated by fractional distillation at a refinery, the following fractions are collected:
| Fraction | Percentage by mass |
|---|---|
| Refinery gas | 4% |
| Gasoline | 20% |
| Kerosene | 15% |
| Diesel oil | 18% |
| Fuel oil | 23% |
| Bitumen | 20% |
Calculate the mass of the kerosene fraction obtained from this crude oil. Give your answer in kilograms.
Show your working and give your final answer with the correct unit.
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.
Show answer
150 kg (±1)
(a) 150 kg · must show Calculation showing 15% of 1000, Correct final answer with unit
Also accept: Kerosene mass = (15/100) × 1000 = 150 kg
Common mistakes: Dividing instead of multiplying by the percentage; Not converting the percentage correctly; Giving percentage not mass
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Writes or uses correct expression for mass of kerosene: (15/100) × 1000 or equivalent
M2 (a) · 1 mark · Substitutes the values correctly or shows attempt to calculate 15% of 1000 kg (follow-through)
A1 (a) · 1 mark · Gives the correct final answer, 150 kg, with the unit
Worked solution
The kerosene fraction is 15% of the total crude oil mass.
Final answer: 150 kg