Calculate
the mass of urea (NH2CONH2) required in making 2.5 kg of
0.25 molal aqueous solution.
Solution
Given that
Mass of solution = 2.5 Kg
Molality = 0.25 m
Molar mass of urea (NH2CONH2)
=14 + 2 × 1 + 12 + 16 + 14 + 2 × 1 = 60 g mol−1
Let mass of urea (NH2CONH2)
= w gram
Number
of moles of urea = w / 60 = 0.01667 mol
Mass
of urea in Kg = w/1000 = 0.001w kg
Mass of solvent = total mass - mass
of solute = 2.5 - 0.001 w kg
Use the above formula we get
Cross multiply and solve for the value of w we get
w = 37 g of urea
Given thatMass of solution = 2.5 KgMolality = 0.25 mMolar mass of urea (NH2CONH2) =14 2 × 1 12 16 14 2 × 1 = 60 g mol−1Let mass ofurea (NH2CONH2) = w gramNumber of moles of urea= w / 60 = 0.01667 molMass of urea in Kg= w/1000= 0.001w kgMassof solvent = total mass- massof solute= 2.5- 0.001 w kgUse the above formula we getCross multiply and solve forthe value of w we getw = 37 g of urea
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DeleteHow will we can determine the unit will be gram of the answer
DeleteHow will we can determine the unit will be gram of the answer
DeleteThank you
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ReplyDeleteYes
DeleteHow is w/60 equal to 0.0167 mol?????
ReplyDeleteIt should be 0.0167w....
DeleteIt's 1/60....then u got 0.01667
DeleteHow did u get 0.0167
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ReplyDeleteYes,how w/60 equal to 0.0167mol???
ReplyDelete1÷60=0.0167 or 1w÷60=0.0167
Delete1÷60=0.0167
DeleteW is 1
DeleteI can't understand your answer?
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ReplyDeleteThis comment has been removed by the author.
ReplyDeleteHow did we cross multiply n get 37????
ReplyDeleteCross multiply one not understood
ReplyDeleteHow we get 37 by cross multiply. ??
DeleteCross multiply one not understood
ReplyDelete?...
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