Question
Sat August 11, 2012 By: Soha

a soln cntains h2so4 20% by mass its density is 1.10g/ml what would be its molality

Expert Reply
Sun August 19, 2012
Since it is 20% by mass H2SO4, then mass H2SO4 in 100 g solution =  20 g
and mass H2O in 100 g = 80 g H2O = 0.080 kg

So, moles H2SO4 in 100 g solution = mass / molar mass = 20 g / 98.086 g/mol = 0.2039 mol


molality = moles solute / kg solvent
= 0.2039 mol / 0.080 kg
= 2.5 m
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