34.2 g of sugar was dissolved in water to produce 214.2 g of sugar syrup. Calculate molality and mole fraction of sugar in the syrup. Given C = 12 and O = 16
Answers
Answer:
1). Mole fraction of sugar in syrup = 1/101
2). Molality of sugar in syrup = 0.5 mol/ kg
>> NOTE : MOLARITY CAN'T BE CALCULATED WITH GIVEN MASS, IT IS ONLY CALCULATED WITH VOLUME, BUT MOLALITY CAN BE CALCULATED.
Explanation:
1). Mole fraction :
>>no. of moles of sugar(solute)/total moles of solution(solution)
(1). sugar = C12H22011
Weight of sugar = 34.2g (given)
Molar mass of sugar = 342 g/mol
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>> mole of sugar = 34.2/342 = 1/10 mole
(II). Water = H2O
Weight of water = 214.2-34.2=180 g Molar mass of water = 18 g/mol
>> mole of water = 180/18 = 10 mole
Now,
>> Mole fraction = (1/10)/(101/10)
= 1/10 × 10/101
[Answer] = 1/101 [ Mole fraction
is a unit less quantity]
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2). Molality
>> If mass is given in gram then,
Molality (weight of solute × 1000)/ = (Molar mass of solute × weight of solvent)
Hence,
weight of solute (Sugar) = 34.2 g (Given)
weight of solvent (water) = 180 g (Given)
Molar mass of solute = = 342 g
» (34.2 x 1000)/(342 × 180)
= 34200/61560
= 0.5 mole/Kg [Answer]
GIVEN:-
- Mass of solute
- Molar mass of sugar
TO FIND:-
Molality and mole
EXPLANATION:-
(1)We know:-
Now let's calculate mass of water,
Mass of water=214.2-34.2
Mass of water=180 gm
Mass of water >180/1000 kg
So the molality is 0.555 M
So total number of moles=10+0.1
==>10.1
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(2)
So the total mole fraction of syrup is 0.0099