Given the balanced equation representing a reaction:2Na(s) + Cl2(g) → 2NaCl(s) + ener

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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