Question

How many grams of water in a 6.0 m HCl solution contains 0.25 grams of HCl?

Answer 1

Molar mass of HCl,

MM = 1*MM(H) + 1*MM(Cl)

= 1*1.008 + 1*35.45

= 36.458 g/mol

mass(HCl)= 0.25 g

we have below equation to be used:

number of mol of HCl,

n = mass of HCl/molar mass of HCl

=(0.25 g)/(36.458 g/mol)

= 6.857*10^-3 mol

molality = number of mol of HCl / mass of water in Kg

6.0 = 6.857*10^-3 / mass of water in Kg

mass of water in Kg = 1.143*10^-3 Kg

mass of water = 1.1 g

Answer: 1.1 g