June 2017 NY Regents Chemistry Exam
35 Given the balanced equation representing a reaction: 2Na(s) + Cl2(g) → 2NaCl(s) + energy If 46 grams of Na and 71 grams of Cl2 react completely, what is the total mass of NaCl produced? (1) 58.5 g
(2) 117 g (3) 163 g
(4) 234 g
Solution: According to the conservation of mass, mass of the reactants must be equal to the mass of products. Therefore mass of Na + mass of Cl2 = mass of NaCl
46g+71g = mass of NaCl
117 g = mass of NaCl
Answer: 2
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