Question

If you wanted to make 0.800 Liters of a 0.531 M solution of Nickel(II) chloride, NiCl2, how many grams of NiCIZ

would you need? Use the unit canceling method to determine the grams of NiCl2
Molar mass= 129g/mol. Moles = 0.4248
.

Answer 1

• 54.8g

Step-by-step explanation:

1. Calculate the number of moles of NiCl₂

a) Identify the known variables

• V =0.800 liters
• M = 0.531M
• n = ?

b) Formula

`M=(n)/(V)`

c) Clear n

`n=M* V`

g) Substitute and compute

`n=0.531M/times 0.800liters=0.4248mol`

2. Convert moles to grams

a) molar mass of NiCl₂

• 129g/mol (shown in the problem)

b) Unit canceling method

Use the factors in order to cancel the units to obtain grams

`0.4248mol* 129(g)/(mol)=54.7992g`

Note that the mol unit appears on the numerator and denominator, so it cancels leaving just g (grams).

c) Round to 3 signficant figures

`54.8g`