Question

34.2 g of glucose is dissolved in 400 g of water. calculate percentage by mass of glucose solution.

Answer 1

a/c to question, 34.2g of glucose is dissolved in 400g of water.

so, mass of glucose (solute)= 34.2g

mass of water (solvent) = 400g

mass of solution = mass of solute + mass of solvent

so, mass of glucose solution = mass of glucose + mass of water

= 34.2g + 400g

= 434.2g

now, percentage by mass of glucose solution =(mass of glucose/mass of solution) × 100

= (34.2/434.2) × 100

= 7.87 %

hence, percentage by mass of glucose solution is 7.87%

[extra point : you can also find molality of glucose. as you know molality = no of mole of solute/mass of solvent in kg .

here, mass of solute = 34.2g

molar mass of glucose (solute) = 180g/mol

mass of solvent (water) = 400/1000 =0.4kg

so, molality = (34.2/180)/0.4 = 0.475m]

Answer 2

Hi,

Here is your answer,

 Percentage by mass = Mass of component/Mass of solution × 100  {FORMULA}
Glucose  = 34.2 gm 

We know that,

Mass of solution
Mass of water 
Mass of glucose 

Mass of solution = mass of water + mass of Glucose 

= 400 + 34.2 gm = 434.2 


Therefore, the percentage of the mass = 34.2/434.2 × 100

= 3420/434.2 

= 7.87 % Mass of the glucose solution.


Hope it helps you !