Question

What is the molarity of a 0.75 L solution that contains 9.2 g of NaCl?

Answer 1

The molarity of the solution is 0.209 M.

Molarity is an expression of the concentration of a compound and it is represented in mole/liter.

So, we need to know how many moles tha sample has.

- First, with the molar mass of the NaCl molecule we calculate the number of moles conteined in 9.2g of NaCl:

NaCl molar mass= 58.44g/mol

`\frac{9.2g\text{ . 1mol}}{58.44g}=\text{ 0.157 moles}`

- Second, molarity is expressed in 1 liter, so we calculate the number of moles that are conteined in 1 liter:

`\frac{1L\text{ . 0.157moles}}{0.75L}=0.209\text{ moles}`

- So, the molarity of the solution is 0.209 M.