15.434 g of kcl (m. m 74.55 g/mol) is dissolved in water up t a total volume of 500.0 mL. the density of this solution is 1.02 g/mL. what is the concentration of he solution in molality

Question

Roger

Chemistry

29 September, 07:22

15.434 g of kcl (m. m 74.55 g/mol) is dissolved in water up t a total volume of 500.0 mL. the density of this solution is 1.02 g/mL. what is the concentration of he solution in molality

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Answers (1)

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Ryker · Answer 1

0.412mol/Kg

Explanation:

First, let us fine the number of mole of KCl ... This is illustrated below

Mass of KCl = 15.434g

Molar Mass of KCl = 74.55 g/mol

Number of mole = Mass / Molar Mass

Number of mole KCl = 15.434/74.55 = 0.21mole

Now, let us calculate the mass of the water in kg. This can be achieved by doing the following:

Density = 1.02 g/mL

Volume = 500mL

Mass = ?

Mass = Density x volume

Mass of water = 1.02 x 500 = 510g

Converting 510g to kg, we have: 510/1000 = 0.51kg

Now we calculate for the molality as follows:

Mole of the solute = 0.21mole

Mass of the solvent = 0.51Kg

Molality = mole of solute / mass of solvent

Molality = 0.21/0.51

Molality = 0.412mol/Kg