I might go with d it seems right to me hope this helps.
Answer is: mass od zinc is 392,28 g.
N(Zn) = 3,6·10²⁴.
n(Zn) = N(Zn) ÷ Na.
n(Zn) = 3,6·10²⁴ ÷ 6·10²³ 1/mol.
n(Zn) = 6 mol.
m(Zn) = n(Zn) · M(Zn).
m(Zn) = 6 mol · 65,38 g/mol.
m(Zn) = 392,28 g.
Na - Avogadro number.
n - amount of substance.
M - molar mass.
The grams that would be produced from 7.70 g of butanoic acid and excess ethanol is 7.923grams
calculation
Step 1: write the chemical equation for the reaction
CH3CH2CH2COOH + CH3CH2OH → CH3CH2CH2COOCH2CH3 +H2O
step 2: find the moles of butanoic acid
moles= mass/ molar mass
= 7.70 g/ 88 g/mol=0.0875 moles
Step 3: use the mole ratio to determine the moles of ethyl butyrate
moles ratio of CH3CH2CH2COOH :CH3CH2CH2COOCH2CH3 is 1:1 therefore the moles of CH3CH2CH2COOCH2CH3 = 0.0875 x78/100=0.0683moles
step 4: find mass = moles x molar mass
= 0.0683 moles x116 g/mol=7.923grams
