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Most of the fuels used today are obtained from crude oil - Edexcel - GCSE Chemistry Combined Science - Question 1 - 2019 - Paper 1
Question 1
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Most of the fuels used today are obtained from crude oil.
(a) Which statement about crude oil is correct?
1. A crude oil is a compound of different hydrocarbons ... show full transcript
Worked Solution & Example Answer:1
Most of the fuels used today are obtained from crude oil - Edexcel - GCSE Chemistry Combined Science - Question 1 - 2019 - Paper 1
Step 1
Which statement about crude oil is correct?
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Answer
The correct statement is B: crude oil is a mixture of hydrocarbons. This is because crude oil consists of various hydrocarbon chains and rings that differ in their molecular composition.
Step 2
State a use for each of these fractions.
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Answer
Kerosene is commonly used as a fuel in jet engines and for heating. Diesel oil is often used in diesel engines for vehicles and machinery.
Step 3
Choose a property.
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Answer
A suitable property to compare is boiling point. Kerosene has a lower boiling point than diesel oil.
Step 4
Explain, using these formulae, why butane and pentane are neighbouring members of the same homologous series.
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Answer
Butane (C₄H₁₀) and pentane (C₅H₁₂) differ by one carbon atom (C) and two hydrogen atoms (H), which is characteristic of a homologous series. Each successive member has one more carbon atom and two more hydrogen atoms, following the general formula CₙH₂ₙ₊₂.
Step 5
Calculate the mass of carbon in 100 g of butane.
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Answer
To find the mass of carbon in butane, use the formula:
Determine the mass fraction of carbon in butane:
Butane (C₄H₁₀) contains 4 carbon atoms.
The molar mass of carbon is 12.0 g/mol.
Total mass of carbon in butane = 4 × 12.0 g = 48.0 g.
Calculate mass fraction of carbon in 100 g of butane:
Mass of carbon = (48.0 g / 58.0 g) × 100 g = 82.76 g.
