WAEC Chemistry 2022 Objective — Question 32
Question 32 of 50 from the West African Examinations Council (WAEC) Chemistry 2022 Objective paper, with the correct answer and a full explanation.
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What is the percentage composition of carbon in Ca(HCO3)2? [Ca=40.0, O=16.0, H=1.0]
- A. 22.2% B
- B. 14.8% CCorrect
- C. 1.4% D
- D. 3.7%
Explanation
Molar mass of Ca(HCO3)2 = 40+2(1+12+16×3) = 40+2(61) = 162 g/mol. Since there are 2 carbon atoms, % C = (2×12)/162 × 100% = 14.8%.
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