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This question is about equilibrium - AQA - A-Level Chemistry - Question 5 - 2021 - Paper 2
Question 5
This question is about equilibrium. 0 5.1 1 mol of a diester with molecular formula C2H4O2 is added to 1 mol of water in the presence of a small amount of catalyst.... show full transcript
Worked Solution & Example Answer:This question is about equilibrium - AQA - A-Level Chemistry - Question 5 - 2021 - Paper 2
Step 1
0 5.1 Amount in the mixture
Answer
At the start, we have 1 mol of diester and 1 mol of water. The equilibrium equation is given as:
C2H4O2(l) + 2 H2O(l) ⇌ 2 CH3COOH(l) + HO(CH2)2OH(l)
Since 2 mol of ethanoic acid are formed at equilibrium, we denote the changes in terms of x. The amounts at equilibrium can be defined as:
- Diester:
- Water:
- Acid:
- Diol:
Step 2
Step 3
0 5.3 Calculate the amount of water
Answer
Using the equilibrium concentrations from Table 3:
- Amount of diester: mol
- Amount of acid: mol
- Amount of diol: mol
The equilibrium expression is given by:
Substituting the known values:
Solving for [Water], we calculate:
- Calculate the numerator:
- Rearranging the equation:
- Extracting the square root gives the final amount of water in mol.