Short Answer TypeCalculate the vapour- pressure lowering of water when5.67g of glucose, C6H12O6 is dissolved in 25.2 g water at 250C. The vapour pressure of water at 250C is 23.8 mmHg. What is the vapour pressure of the solution?
What will be the boiling point of bromine when 87.25 x 10-3 g of Sulphur is added to 39g of bromine? Bromine boils at 332.15K [Kbfor Br2 -5.2K kgmole-1]
The freezing point of a solution containing 0.2g of acetic acid in 20.0 g of benzene is lowered by 0.450C. calculate the degree of association of acetic acid in benzene. (Kf for benzene =5.12K kg mol-1)
Calculate the amount of ice that will separate out on cooling a solution containing 50g of ethylene glycol in 200g water -9.30C (Kf for water =1.86K kf mol-1).
Long Answer TypeAnswer:
osmotic pressure is proportional to the molarity, C of the solution at a given temperature T. Thus:
Π = C R T
Here Π is the osmotic pressure and R is the
gas constant.
Π = (n2 /V) R T
Here V is volume of a solution in litres containing n2 moles of solute.
If w2 grams of solute, of molar mass, M2 is present in the solution, then
n2 = w2 / M2 and we can write,
Thus, knowing the quantities w2, T, Π and V we can calculate the molar mass of the solute.
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