Answer:
The balanced chemical equation for the reaction between butanoic acid and ethanol to produce ethyl butyrate is:
CH3CH2CH2COOH + C2H5OH → CH3CH2CH2COOC2H5 + H2O
From the equation, we can see that 1 mole of butanoic acid reacts with 1 mole of ethanol to produce 1 mole of ethyl butyrate and 1 mole of water. The molar mass of butanoic acid is 88.11 g/mol and the molar mass of ethyl butyrate is 116.16 g/mol.
To find out how many grams of ethyl butyrate can be produced from 8.55 g of butanoic acid, we first need to determine how many moles of butanoic acid are present:
moles of butanoic acid = mass / molar mass = 8.55 g / 88.11 g/mol = 0.097 mol
Since the reaction has a yield of 78.0%, we can calculate the theoretical yield of ethyl butyrate as follows:
theoretical yield = moles of butanoic acid × (1 mol ethyl butyrate / 1 mol butanoic acid) × 78.0%
= 0.097 mol × 1 × 0.78
= 0.0757 mol
Finally, we can calculate the actual mass of ethyl butyrate produced using its molar mass:
mass of ethyl butyrate = moles of ethyl butyrate × molar mass
= 0.0757 mol × 116.16 g/mol
= 8.80 g
Therefore, from 8.55 g of butanoic acid and excess ethanol, the chemist can produce 8.80 g of ethyl butyrate with the more efficient catalyst.