Three students, A, B and C, are preparing sugar solutions for an experiment. Class 9
Three students, A, B and C, are preparing sugar solutions for an experiment. Class 9
Question 1.
Three students, A, B and C, are preparing sugar solutions for an experiment: Class 9
- Student A dissolves 20 g of sugar in 80 g of water.
- Student B dissolves 20 g of sugar in 100 g of water.
- Student C dissolves 30 g of sugar in 80 g of water.
(i) Calculate the mass percentage (% m/m) concentration of sugar in each student’s solution.
(ii) Whose solution is the most concentrated? Explain why.
Answer:
(i) Student A:
Total mass = 20 + 80 = 100 g.
% m/m = ([latex]\frac{20}{100}[/latex]) × 100 = 20% m/m
Student B:
Total mass = 20 + 100 = 120 g
% m/m = ([latex]\frac{20}{120}[/latex]) × 100 = 16.67% m/m
Student C:
Total mass = 30 + 80 = 110 g.
% m/m = ([latex]\frac{30}{100}[/latex]) × 100 = 27.27% m/m
(ii) Student C's solution is the most concentrated (27.27% m/m). This is because Student C dissolved the largest amount of sugar (30 g) in the smallest amount of solvent (80 g water), giving the highest mass percentage. Concentration depends on both the amount of solute and the total mass of the solution - more solute in less solvent means higher concentration.