Question

Need little help pls

Answer 1

Answer:

0.354 molal

Explanation:

The molarity (M) or the concentration of a solution is defined as the number of moles of a compound in the solution per liter of solution (mol/L), whereas molality, is defined as the number of moles of a compound in the solution per kg of the compound (mol/kg).

Given that the density of the solution is 1.202 g/mL, which is equivalent to 1.202 kg/L. Since the prefix mili- denotes a factor of one thousandth ( $10^{-3}$ ) and kilo- denotes a factor of one thousand ( ${10}^3$ ),

$1.202 \ \frac{g}{mL} \ = \ 1.202 \ \frac{g}{(10^{-3}) L} \ = \ 1.202 \ \frac{{10}^3g}{L} \ = \ 1.202 \ \frac{kg}{L}$.

To calculate the corresponding molality of the solution, the formula

$Molality \ (mol/kg) \ = \ \frac{Molarity \ (mol/L)}{Density \ (kg/L)}$ is used.

Therefore,

$Molality \ = \ \frac{0.426 \ mol/L}{1.202 \ kg/L} \ = \ 0.354 \ mol/kg \ \ (3 \ s.f.)$