Nitration of 1.70 g of methyl benzoate (M_r = 136.0) produces methyl 3-nitrobenzoate (M_r = 181.0) - AQA - A-Level Chemistry - Question 29 - 2021 - Paper 3
Question 29
Nitration of 1.70 g of methyl benzoate (M_r = 136.0) produces methyl 3-nitrobenzoate (M_r = 181.0). The percentage yield is 65.0%.
What mass, in g, of methyl 3-nitr... show full transcript
Worked Solution & Example Answer:Nitration of 1.70 g of methyl benzoate (M_r = 136.0) produces methyl 3-nitrobenzoate (M_r = 181.0) - AQA - A-Level Chemistry - Question 29 - 2021 - Paper 3
Step 1
Calculate the moles of methyl benzoate
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Answer
To find the moles of methyl benzoate, we use the formula:
moles=Mrmass
Given that the mass is 1.70 g and the molar mass (M_r) is 136.0 g/mol:
moles of methyl benzoate=136.0 g/mol1.70 g=0.0125 moles
Step 2
Determine the theoretical yield of methyl 3-nitrobenzoate
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Answer
The reaction is assumed to yield 1 mole of methyl 3-nitrobenzoate for each mole of methyl benzoate used.
Thus, the theoretical yield (in grams) can be calculated as:
Theoretical yield=moles of methyl benzoate×Mr of methyl 3-nitrobenzoate
which gives:
Theoretical yield=0.0125 moles×181.0 g/mol=2.28125 g
Step 3
Calculate the actual yield of methyl 3-nitrobenzoate
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The actual yield can be calculated using the percentage yield formula:
Actual yield=(100Percentage yield)×Theoretical yield
Thus:
Actual yield=(10065.0)×2.28125 g≈1.47981 g
This rounds to 1.48 g, and the closest option provided is 1.47 g.