Post-UTME Chemistry 2015 Objective — Question 20

Question 20 of 20 from the Post-UTME Screening (Post-UTME) Chemistry 2015 Objective paper, with the correct answer and a full explanation.

If a sample of fructose C6H12O6 contains 24g of carbon, calculate the mass of oxygen in it. [C=12, H=1, O=16]

A. 24g
B. 32gCorrect
C. 48g
D. 64g

Explanation

Moles of C = 24/12 = 2mol. Since fructose has 6 C and 6 O atoms per molecule, moles of fructose = 2/6 = 1/3 mol, so moles of O = 6 x 1/3 = 2mol. Mass of O = 2 x 16 = 32g.

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