Question

How much ch2o is needed to prepare 445 ml of a 2.65 m solution of ch2o?

Answer 1

Answer: 35.4 grams

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$

where,

Molality = 2.65

n= moles of solute =?

 $V_s$ = volume of solution in ml = 445 ml

Putting in the values we get:

$2.65=\frac{n\times 1000}{445ml}$

$n=1.18$

Mass of solute in g=$moles\times {\text {molar mass}}=1.18mol\times 30.02g/mol=35.4g$

Thus 35.4 grams of $CH_2O$ is needed to prepare 445 ml of a 2.65 m solution of $CH_2O$.