Question

OF 16.2 percent Uy HSS SUTULUI. (10) Calculate the number of e of solute that would be needed to make each of the following solutions: (a) 2.00 x 10 ml of 0.100 M NaBr (b) 2.50 x 10 mL of 0.200 M KOH

Answer 1

By definition molarity of a solution ,M is number of moles of solute dissolved in 1 liter of solution

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Molar mass of NaBr = 102.89 g/mol

Molar mass of KOH = 56.1 g/mol

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a)

$Molarity,M = \frac{massof solute ,m}{Molar mass of solute}*\frac{1000}{Vml}$

V = volume of solution in ml

$Molarity,M = \frac{massof solute ,m}{102.89 g/mol}*\frac{1000}{200 ml}$

  $0.1 M = \frac{massof solute ,m}{102.89 g/mol}*\frac{1000}{200 ml}$

mass of solute = (0.1 * 102.89 g/mil * 200 ml) /1000

= 2.058 g

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b ) Similarly mass of KOH , m is calculated as follows-------------------

$0.2 M = \frac{massof solute ,m}{56.1 g/mol}*\frac{1000}{250 ml}$

m = (0.2 M * 56.1 g/mol * 250 ml ) / 1000

= 2.805 g