What mass of calcium hydroxide forms when 0.80 g of calcium reacts completely with water (Ca = 40, O = 16, H = 1)?
Correct answer B. 1.48 g
Explanation
Ca + 2H₂O → Ca(OH)₂ + H₂. Moles of Ca = 0.80/40 = 0.020 mol, so 0.020 mol Ca(OH)₂ forms. Mass = 0.020 × 74 = 1.48 g.
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