GATE 2020 BT – Question 29
Dry yeast biomass has elemental composition $CH_{1.6}O_{0.4}N_{0.2}S_{0.0024}P_{0.017}$. Find carbon contribution to dry biomass in percent, rounded to 2 decimals. Atomic weights H, C, N, O, P, S are 1, 12, 14, 16, 31, 32, respectively.
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Correct answer: 51.01 to 52.99
Explanation
On the empirical-formula basis, carbon contributes 12 mass units. Total mass is $12+1.6+0.4(16)+0.2(14)+0.0024(32)+0.017(31)=23.4038$. Carbon mass percentage is $100(12)/23.4038=51.27\%$. The elemental subscripts are molar ratios; they must be weighted by atomic mass.