Question

Copper reacts with silver nitrate through single replacement.

a. If 2.25 g of silver are produced from the reaction, how many moles of copper(II) nitrate are also produced?
b. How many moles of each reactant are required in this reaction?

Answer 1

• Part a) 0.0104 moles copper(II) nitrate.

• Part b)

i) 0.0418 mole Cu

ii) 0.0209 mol Ag NO₃

Step-by-step explanation:

1) Balanced chemical reaction (single replacement):

In a single replacement reaction a more acitve metal (Cu) replaces a less active metal (Ag)

• Cu + 2 Ag NO₃ → Cu (NO₃)₂ + 2 Ag

2) Mole ratio:

• 1 mole Cu : 2 mole Ag NO₃ : 2 mole Ag

3) Moles of Ag

• n = mass in grams / atomic mass
• atomic mass of Ag: 107.868 g/mol
• n = 2.25 g / 107.868 g/mol = 0.0209 mol Ag

4) Moles of copper(II) nitrate:

• Set the proportion using the mole ratio:

• 2 mole Ag / 1 mole Cu (NO₃)₂ = 0.0209 mole Ag / x

• Solve: x = 0.0209 / 2 mole Cu (NO₃)₂ = 0.0104 moles Cu(NO₃)₂

That is the answer of part a: 0.0104 moles copper(II) nitrate.

5) Moles of each reactant

i) Cu:

• Set a proportion using the theoretical mole ratio

1 mole Cu / 2 mole Ag = x / 0.0209 mol Ag

• Solve for x: x = 0.0209 / 2 mole Cu = 0.0418 mole Cu

ii) Ag NO₃

• Set a proportion using the teoretical mole ratio

2 mole Ag NO₃ / 2 mole Ag = x / 0.0209 mole Ag

• Solve for x: x = 0.0209 mol Ag NO₃