Question

Q1. 0.5g of salt is dissolved in 25g of water. Calculate the percentage of the salt in the solution.

Q2. A solution of urea in water contains 16g of it in 120g of solution. Find out the mass percentage of the

solution

Q3. A solution has been prepared by mixing 5.6ml of alcohol with 75ml of water. Calculate the

percentage(by volume) of alcohol in the solution.

Q4. A solution contains 30g of glucose, 20g of salt in 500ml of water. Calculate the mass percent of glucose

and salt.

(density of water= 1g/ml)

Q5. Calculate the mass of water and glucose required to make 250g of 40% solution of glucose.

Q6. How much water should be mixed with 12ml of alcohol so as to obtain 12% alcohol solution?

Q7. Whys is blood said to be a mixture and graphite an element? Mention any one reason for each.

Q8. Crystallization is a better technique than simple evaporation. Explain giving two reasons.

Q9. Using a flow chart show the process of obtaining different gases from air.

Q10. State the principle used in separating different components of a mixture by the method of

centrifugation. list any two applications of this method.

Q11. (A) A solution contains 30g of sugar in 210ml of water. Calculate the concentration in terms of mass

by volume percentage of the solution.

(B) Why does the solution of sugar and water not show tyndall effect whereas the mixture of water

and milk shows?

Q12. Explain why filter paper cannot be used to separate colloids.

Answer 1

Q1.
in 25g water,the amount of the salt =0.5g
„ 1g. „ „ „ „ „ = 0.5/25g
„ 100g „ „ „ „ „ =0.5/25×100g
= 2g
therefore, the percentage of the salt =2%