Question

2. How many grams of zinc will be formed if 32.0 g of copper reacts with zinc nitrate? Copper(I)nitrate is the other product.

Answer 1

Answer:

16.46 g.

Explanation:

• It is a stichiometry problem.

• We should write the balance equation of the mentioned chemical reaction:

2Cu + Zn(NO₃)₂ → Zn + 2Cu(NO₃).

• It is clear that 2.0 moles of Cu reacts with 1.0 mole of Zn(NO₃)₂ to produce 1.0 mole of Zn and 2.0 moles of Cu(NO₃).

• We need to calculate the number of moles of the reacted Cu (32.0 g) using the relation:

n = mass / molar mass

• The no. of moles of Cu = mass / atomic mass = (32.0 g) / (63.546 g/mol) = 0.503 mol.

Using cross multiplication:

2.0 moles of Cu produces → 1.0 mole of Zn, from the stichiometry.

0.503 mole of Cu produces → ??? mole of Zn.

• The no. of moles of Zn produced = (1.0 mol)(0.503 mol) / (2.0 mol) = 0.2517 mol.

∴ The grams of Zn produced = no. of moles x atomic mass of Zn = (0.2517 mol)(65.38 g/mol) = 16.46 g.