Describe a method of determining molar mass of a non-volatile solute from vapour pressure lowering.
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Answered by
7
calculate the mass of non volatile solute ( molecular mass = 40) which should be dissolved in 114g of octane to reduce its vapour pressure to 80%?
in this question if we are directly applying the formulae
(psolvent - psol n )/p solvent = (wb *ma)/(mb*wa)
putting p solvent = x
psol n = 0.8x
mb = 40
wa = 114 = ma
we get answer = 8g which is incorrect as correct answer is 10g
could you kindly explain why is it so?
as we can follow any method then answer should come correct?
in this question if we are directly applying the formulae
(psolvent - psol n )/p solvent = (wb *ma)/(mb*wa)
putting p solvent = x
psol n = 0.8x
mb = 40
wa = 114 = ma
we get answer = 8g which is incorrect as correct answer is 10g
could you kindly explain why is it so?
as we can follow any method then answer should come correct?
Answered by
4
Answer:
From Raults Law
(po-p1)/po = X (molefraction)
(po-p1)/po = n2/n1 (if n2 is smaller than n1 if not then n1+n2)
(po-p1)/po = w2/m2*m1/w1
so by these equation we can find molar massxplanation:
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