Question

Given: 2AgNO3 + NiCl2 -> 2AgCl + Ni(NO3)2

Answer 1

Answer: AgNO3 is the limiting reactant.

Explanation:

1) Balanced chemical equation:

Given: 2AgNO3 + NiCl2 → 2AgCl + Ni(NO3)2

2) Mole ratios:

2 mol AgNO3 : 1 mol NiCl2 : 2 mol AgCl : 1 mol Ni(NO3)2

3) Convert 0.847 g of AgNO3 to moles

n = mass in grams /  molar mass

molar mass = sum of the masses of all the atoms in the molecular formula

molar mass of AgNO3 = 107.9 g/mol + 14.0 g/mol + 3*16.0 g/mol = 169.9 g/mol

n = 0.847 g / 169.9 g/mol = 0.00499 mol AgNO3

4) Convert 0.650 g of NiCl2 to moles

n = mass in grams / molar mass

molar mass NiCl2 = 58.7 g/mol + 2*35.5 g/mol = 129.7 g/mol

n = 0.650 g / 129.7 g/mol = 0.00501 mol NiCl2

5) Compare the theoretical mole ratio with the actual ratio:

Theoretical mole ratio: 2 mol AgNO3 / 1 mol NiCl2
Actual ratio: 0.00499 mol AgNO3 / 0.00501 mol Ni Cl2 ≈ 1:1

Therefore, the amount of AgNO3 is half the required amount need to react with all the NiCl2, which means that the AgNO3 will react completely and there will be an excess of NiCl2. The reactant that is consumed completely while the other is left, is the limiting reactan. This is, AgNO3 is the limiting reactant.