The molecular formula of butene is C₄H₈ - Edexcel - GCSE Chemistry Combined Science - Question 2 - 2018 - Paper 1
Question 2
The molecular formula of butene is C₄H₈.
Which of the following is the empirical formula of butene?
A. C₁H
B. C₂H₂
C. C₄H₄
D. (CH₂)₄
(b) Calculate the relative form... show full transcript
Worked Solution & Example Answer:The molecular formula of butene is C₄H₈ - Edexcel - GCSE Chemistry Combined Science - Question 2 - 2018 - Paper 1
Step 1
Which of the following is the empirical formula of butene?
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Answer
The empirical formula can be determined by simplifying the molecular formula, C₄H₈. To find the simplest whole number ratio of carbon to hydrogen, divide both by 4:
extC:44=1 and H: 48=2
Thus, the empirical formula is C₁H₂, which corresponds to option B.
Step 2
Calculate the relative formula mass of butene, C₄H₈.
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Answer
The relative formula mass can be calculated using the atomic masses:
extRelativeformulamass=(4×12)+(8×1)=48+8=56
Thus, the relative formula mass of butene is 56.
Step 3
Balance the equation for this reaction by putting numbers in the spaces provided.
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Answer
The combustion of butene can be represented by the balanced equation:
C4H8+6O2→4CO2+4H2O
Thus, the numbers to fill in are:
1st blank: 6
2nd blank: 4
3rd blank: 4.
Step 4
Describe the test to show that a gas is carbon dioxide.
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Answer
To test for carbon dioxide, bubble the gas through limewater (a dilute solution of calcium hydroxide). If carbon dioxide is present, it will react with the calcium hydroxide to form calcium carbonate, which is insoluble and causes the limewater to turn cloudy or milky.
