WAEC Chemistry 2015 Objective — Question 21
Question 21 of 50 from the West African Examinations Council (WAEC) Chemistry 2015 Objective paper, with the correct answer and a full explanation.
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The number of oxygen molecules present in 16.0 g of the gas is [Avogadro's number = 6.02×10²³]
- A. 6.02×10²²
- B. 6.02×10²³
- C. 3.01×10²³Correct
- D. 1.51×10²³
Explanation
Moles of O₂ = 16/32 = 0.5 mol. Number of molecules = 0.5 × 6.02×10²³ = 3.01×10²³.
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