# Class 9 Science CBSE Three and Five Marks questions Is Matter around us pure

Assignments

Given below are the Class 9 Science CBSE Three and Five Marks questions Is Matter around us pure
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## 3-Marks Questions

Question 1. Write down the processes involved in sequential order to get the supply of drinking water to your home from the water works.
Question 2.Define solubility. How does solubility. How does solubility of a solid in water change with temperature?

Question 3.Two students A and B were given 10 ml of water in a bowl and a plate respectively. They were told to observe the rate of evaporation. Name the student whose water evaporates faster and explain its reason.

Question 4.Why the inter-conversion of states of matter is considered as a physical change? Give three reasons to justify your answer.
Question 5.(a) Name the separation technique you would follow to separate
(i) Dyes from black ink.
(ii) A mixture of salt and ammonium chloride
(iii) Cream from milk
(iv) Sodium chloride from its solution in water
(b) State the principle used in separating a mixture of two immiscible liquids.

Question 6.How many litres of 15% (mass/ volume) sugar solution would it take to get 75 g of sugar?

Question 7.During an experiment the students were asked to prepare a 10 % (Mass/ Mass) solution of sugar in water. Ramesh dissolved 10 g of sugar in 100 g of water while Sarika prepared it by dissolving 10 g of sugar in water to make 100 g of the solution.
a)Are the two solutions of the same concentration?
b)Compare the mass % of the two solutions.

Question 8.Calculate the mass of sodium sulphate required to prepare its 20% (mass percent) solution in 100 g of water.

Question 9.Give an example for each of following:
a)Solid -liquid homogeneous mixture
b)Gas- gas homogeneous mixture
c)Liquid -liquid heterogeneous misture

Question 10.Distinguish between homogeneous and heterogeneous mixtures. Classify the following mixtures as homogeneous and heterogeneous:
(i) Tincture of iodine (ii) Smaoke
(iii) Brass(iv) Sugar solution
Question 11.A teacher told three students A, B and C to prepare 25% solution (mass by volume) of KOH. Student A dissolved 25 g of KOH in 100 g of water, student B dissolved 25 g of KOH in 100 mL of water and student C dissolved 25 g KOH in water and made the volume 100 mL. Which one of them has made required 25% solution? Give your answer with reason.

Question 12.Calculate the mass of water and mass of glucose required to make 250 g of 40% solution of glucose.

Question 13.‘Colloidal solution appears to be homogeneous but actually it is heterogeneous.’ Give justification for this statement.
Question 14.When a fine beam of light enters a room through a small hole, Tyndall effect is observed. Why does this happen? Give one more example where this effect can be observed.
Question 15.With the help of a flow diagram, show the process of obtaining different gases from air. If the boiling point of oxygen, argon and nitrogen are – 183o C, - 86o C and – 196o C respectively, which gas gets liquefied first as the air is cooled?
Question 16.Differentiate between miscible and immiscible liquids. Give an example of each.
Question 17.Write the role of following in water purification system:
(a) Sedimentation Tank(b) Loading tank(c) Chlorination tank
Question 18.Crystallization is better technique than simple evaporation technique. Justify this statement by giving two reasons.
Question 19.(i) Name a technique to separate a mixture of two or more miscible liquids for which difference in boiling points is less than 25 K.
(ii) Describe the structure of the column used in the above technique. Why is it used?
Question 20.When do we use the process of centrifugation? State the principle involved in this process. List its any two applications in our daily life.
Question 21.A mixture contains two liquids A and B, which differ in tyheir boiling points by 20 K. suggest a suitable process to separate them. Draw a neat labeled diagram to explain this process.
Question 22.Define distillation. What type of mixture can be separated by distillation?
Question 23.What is the principle of separating funnel technique? How it is useful in extraction of iron from its ore?
Question 24.List three differences between a physical change and a chemical change.

Question 25.Differentiate between, an element and a compound (any two points) with one example each.
Question 26.(i) Name the compound formed on heating a mixture of iron filings and sulphur.
(ii) If dilute HCI is added to above compound then name the gas evolved and write down its two properties.