The density of solution prep. by dissolving 120g urea in 1kg h2o is 1.15g/mL. Molarity?
A 2.05M
B 0.50M
C 1.78M
D 1.02M
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As We know that
Density of solution = Mass of solution / Volume of solution
therefore , volume of solution = Mass / density = 120+1000 g/ 1.15 g ml-1
= 1120 *100 / 115 = 973.91 ml = 974 * 10 -3 litres
Now ,
n (no. of moles of solute) = 120 g / 60.05 g = 2 mol [since, molecular mass of urea is 60.05 g]
Now ,M(Molarity) = n (no. of moles of solute)/ Volume of solution in litres
Molarity = 2 / 974 * 10-3
Molarity = 2000/974 = 2.05 M
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