Question

What mass of NaCl is dissolved in 150 g of water in a .050 msolution?

Answer 1

Answer:

0.4383 g

Explanation:

Molality is defined as the moles of the solute present in 1 kg of the solvent.

It is represented by 'm'.

Thus,  

$Molality\ (m)=\frac {Moles\ of\ the\ solute}{Mass\ of\ the\ solvent\ (kg)}$

Given that:

Mass of solvent, water = 150 g = 0.15 kg ( 1 g = 0.001 g )

Molality = 0.050 m

So,

$0.050=\frac {Moles\ of\ the\ solute}{0.15}$

$Moles = 0.050\times 0.15\ mol= 0.0075\ mol$

Molar mass of NaCl = 58.44 g/mol

Mass = Moles*Molar mass = $0.0075\times 58.44\ g$ = 0.4383 g