Question

10) In a solution of NiCl2, the Cl- concentration is 0.059 M. How many grams of NiCl2 are in 462 mL of this solution?

Answer 1

5.299 grams

Step-by-step explanation

Given:

Concentration of Cl⁻ = 0.059 M

Volume of solution = 462 mL = 0.462 L

What to find:

The grams of NiCl₂ in 462 mL solution

Step-by-step solution:

The first step to write a balanced equation for the dissolution of NiCl₂:

`\text{NiCl}_(2(s))\rightarrow Ni^(2+)+2Cl^-`

From the balanced equation; 1 mole of NiCl₂ produces 2 moles of Cl⁻

Given that the concentration of Cl⁻ = 0.059 M, so the concentration of Ni⁺ will be:

`(\lbrack Cl^-\rbrack)/(2)=(0.059)/(2)=0.0295\text{ }M\text{ }Ni^(2+)`

So that Molarity, M, of NiCl₂ = 0.059 M + 0.0295 = 0.0885 M

`Number\text{ of moles NiCl}_2=Molarity* Vol\text{ume in L}`

Number of moles of NiCl₂ = 0.0885 M x 0.462 L = 0.040887 mol

The last step is to convert the number of moles of NiCl₂ to grams using the formula below:

`\text{Number of moles }=\frac{Mass}{Molar\text{ mass}}`

From the Periodic Table;

Molar mass of NiCl₂ = 129.5994 g/mol

So, mass of NiCl₂ in 462 mL solution = 0.040887 mol x 129.5994 g/mol = 5.299 grams