Question

Which calculation below represents the mass of

copper(II) nitrite (MM = 155.6 g/mol) should be
weighed out to produce 250 ml of a 0.50 M solution?

Answer 1

Answer : The mass of
`Cu(NO_3)_2` in the solution is, 19.4 grams.

Explanation : Given,

Molarity of solution = 0.50 M

Volume of solution = 250 mL

Molar mass of
`Cu(NO_3)_2` = 155.6 g/mole

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

`\text{Molarity}=\frac{\text{Mass of }Cu(NO_3)_2* 1000}{\text{Molar mass of }Cu(NO_3)_2* \text{Volume of solution (in mL)}}`

Now put all the given values in this formula, we get:

`0.50M=\frac{\text{Mass of }Cu(NO_3)_2* 1000}{155.6g/mole* 250mL}`

`\text{Mass of }Cu(NO_3)_2=19.4g`

Therefore, the mass of
`Cu(NO_3)_2` in the solution is, 19.4 grams.