IS MATTER AROUND US PURE

Subject: Science Chapter: 02 – Is matter around us pure?

Each question carries 1 mark:

1. Define an element

2. Name a non –metallic element found in (i) liquid (ii) gaseous state

3. Pick a metalloid from the following: carbon ,silicon phosphorus ,gold

4. Name a metal which is liquid at room temperature

Each question carries 2 marks:


5. What are metalloids ? Give two examples

6. Write any two physical properties of each of metals and non metals

7. Arrange solution suspension and colloid in increasing order of their particle size.

8.Identify the type of change seen during formation of basic copper carbonate on copper

Correct the false statements:

a. Soft drink and soil consist of a single type of particles.

b. Blood will show tyndall effect

c. Tincture of iodine is a mixture of iodine in water.

d. To a saturated solution no more solute can be added at a fixed temperature.

e. On burning graphite no residue will be left.

f. A colloidal solution is a heterogenous mixture and the components can be separated by sedimentation.

g. A mixture of sodium chloride and ammonium chloride can be separated by filtration.

h. Solutions that contain a solvent other than water are called aqueous solutions
.
i .If the proportion of the solute is less ,the solution is said to be concentrated.

j. A change in which the composition of of a substance is altered is called a physical change.

Section B: Extended Exposition
Each question carries 1 mark:

10. Under which category of mixtures will you classify alloys and why?

11.Which of the tubes in figure (a) and (b) will be more effective as a condenser in the distillation apparatus?

Each question carries 2 marks:
1
12

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a.  Solution X is copper sulphate and solution of Y is a mixture of milk and water? Identify true solution and colloid from both of them?
b.  What is your observation in both the beakers when light was being thrown on the beakers from one side?


13. A solution contains 25 g of sugar in 225g of water. Calculate the concentration in terms of mass by mass percentage of the solution.

What is meant by (i) solute (ii) solvent in a solution?

Each question carries 3 marks

14. The melting point of a solid when determined experimentally comes out to be 1600C.But its actual melting point as given in standard books is 1500C.Predict the nature of the solid

15. To an already prepared solution of a solute “A” in water, a small amount of ‘A’ is further added. However it does not dissolve. What does it indicate?

16. You are provided with a mixture of carbon tetrachloride and water. How will you prepare the constituents?

17. Identify the solute and solvent in(i) tincture of iodine (ii)dental amalgam
Which of the following compounds when added to water followed by vigorous stirring forms a true solution ,suspension and a colloid

18. Based on the following characteristics distinguish in tabular form the behaviour of true solution, suspension and colloidal solution

particle size, appearance , visibility , filterability , tyndall effect

Section C: Interpretation & Reasoning
Each question carries 1 mark:

19. Identify solute and solvent in the following solutions :aerated drinks, tincture of iodine, lemon water

20. State one property in which a solution of sugar in water resembles a mixture of sugar and sand and one property in which it differs from it.

Each question carries 2 marks:

21. Water containing 88.8% oxygen and 11.2% is often used as a fire extinguisher. Can a mixture containing the two gases in the same ratio by mass be used for extinguishing fire?


22. Sulphur and iron filings were mixed together and separated into two parts ’X’ and ‘Y’. The part ’X’ was heated strongly while part‘Y’ was kept as such. Dilute HCl was added to both the parts and evolution of gas was noticed in both the cases. Will the gases be the same or different? Explain your answer

23. Two gases ammonia and hydrogen chloride present in separate tubes are mixed together. Have they resulted in a mixture? Explain.

24. A compound is regarded as a pure substance while the mixture is not. Assign reason.
Write the two components of a colloidal solution.Give two examples for a colloidal solution

Each question carries 3 marks

Section D: Problem Solving
Each question carries 3 marks:

28. A solution of acetone contains 30 mL of acetone in 570 mL of water. Calculate the percentage concentration of the solute in the solution.

30. A solution contains 5 g of glucose in 45 g of water. Calculate concentration of solution in mass %.

31. A solution contains 60g of sugar in 480g of water. Calculate the concentration of solution in terms of mass by mass percentage of the solution.

32. 5g of sugar is dissolved in 250ml of solution. Calculate its mass percentage by volume.

33. A solution contains 25 g of sugar in 225g of water. Calculate the concentration in terms of mass by mass percentage of the solution.

34. Calculate the mass of potassium sulphate required to prepare its 10%(mass percent) solution in 100 g of water