How many grams of ester can be obtained from 200 g of 10% methyl alcohol and 200 g of 60%
How many grams of ester can be obtained from 200 g of 10% methyl alcohol and 200 g of 60% butyric acid if the product yield is 50%?
1.Let’s find the mass of CH3OH in the solution.
W = m (substance): m (solution) × 100%, hence
m (substance) = (m (solution) × W): 100%.
m (substance) = (200 g × 10%): 100% = 20 g.
2.Let’s find the amount of CH3OH substance.
M (CH3OH) = 32 g / mol.
n = 20 g: 32 g / mol = 0.625 mol.
Let’s find the mass of Н3ССН2 СН2 СООН in solution.
m (substance) = (200 g × 60%): 100% = 120 g.
M (H3CCH2 CH2 COOH) = 88 g / mol.
n = 120 g: 88 g / mol = 1.36 mol (excess).
Let’s find the quantitative ratios of substances.
Н3ССН2 СН2 СООН + СН3ОН → Н3ССН2 СН2 СООСН3 + Н2О.
For 1 mol of CH3OH, there is 1 mol of H3CCH2 CH2 COOCH3.
Substances are in quantitative ratios 1: 1.
n (Н3ССН2 СН2 СООСН3) = n (СН3ОН) = 0.625 mol.
3.Let’s find the mass Н3ССН2 СН2 СООСН3.
m = nM.
M (Н3ССН2 СН2 СООСН3) = 102 g / mol.
m = 0.625 mol × 102 g / mol = 63.75 g.
63.75 g – 100% (in theory),
X – 50%,
X = (63.75 × 50%): 100% = 31.875 g.
Answer: 31.875 g.