Question

What is the molality (m) of a 36.45% (by weight) solution of HCl in water?

A. 0.0157 m

B. 0.0274 m

C. 1.00 m

D. 15.74 m

E. 63.55 m

Please explain!

Answer #1

molality = (mass of solute/ molar mass of solute) x (1 / mass of solvent in Kg)

Let us assume , mass of solution = 100 g

Given that mass % of HCl = 36.45 %

Hence,

mass of HCl (solute) = 36.45 g

mass of solvent (water)= 100 -36.45 g = 63.55 g = 0.06355 kg

molar mass of HCl = 36.5 g/mol

Hence,

molality = (mass of HCl/ molar mass of HCl) x (1 / mass of water in Kg)

= (36.45 g/36.5 g/mol ) x (1 / 0.06355 kg)

= 15.74 m

Therefore,

molality of given solution = 15.74 m

A
hcl solution is 35.0% (by mass) hcl in water. Determine the
molality in hcl if the solution has a density of 1.15 g/mol

A solution consists of 18.0 g of
hydrochloric acid, HCl, and
91.0 g water and has a density of
1.08 g/mL.
(a)Calculate the weight percent of HCl, (b) the
molality of HCl, (C) the mole fraction of
HCl, and (d) the molarity of HCl
in the solution.

what concentration unit is used in the calculation of osmotic
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C.) Mass fraction
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b. if an aqueous solution is prepared with molality = 8.21 moles
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