The molecular formula of butene is C₄H₈ - Edexcel - GCSE Chemistry - Question 4 - 2018 - Paper 1
Question 4
The molecular formula of butene is C₄H₈.
Which of the following is the empirical formula of butene?
A) CH
B) C₂H₂
C) C₄H₈
D) (CH₂)₄
(b) Calculate the relative formu... show full transcript
Worked Solution & Example Answer:The molecular formula of butene is C₄H₈ - Edexcel - GCSE Chemistry - Question 4 - 2018 - Paper 1
Step 1
Which of the following is the empirical formula of butene?
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Answer
To determine the empirical formula of butene, divide the molecular formula subscripts by the greatest common divisor. The molecular formula is C₄H₈. Both 4 (for C) and 8 (for H) can be divided by 4:
C: 4 ÷ 4 = 1
H: 8 ÷ 4 = 2
Thus, the empirical formula is CH₂, which corresponds to option B.
Step 2
Calculate the relative formula mass of butene, C₄H₈.
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Answer
To calculate the relative formula mass, sum the relative atomic masses of the atoms in C₄H₈:
Carbon (C): 4 × 12 = 48
Hydrogen (H): 8 × 1 = 8
Thus, the total relative formula mass is:
extRelativeFormulaMass=48+8=56
Step 3
When burnt completely in air, butene forms carbon dioxide and water.
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Answer
The combustion of butene can be represented by the reaction:
extC4H8+6extO2→4extCO2+4extH2O
This equation shows that butene reacts with oxygen to produce carbon dioxide and water.
