Chemistry

Is Matter Around Us Pure?

Question:

How elements are further classified?

Answer:

Metals, Non-metals, metalloids.
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Is Matter Around Us Pure?

Q 1.

State the differences between compounds and mixtures.

Q 2.

Identify the following as mixture or compound.
(i) blood
(ii) common salt
(iii) sugar
(iv) brass

Q 3.

What is a solution? What are the properties of a solution?

Q 4.

What are the characteristics exhibited by a pure substance?

Q 5.

What are the differences and similarities between concentration and solubility?

Q 6.

What are the properties of suspensions?

Q 7.

What are the reasons for separating the constituents of a mixture?

Q 8.

Name two properties of a substance to check its purity?

Q 9.

What factors affect the solubility of solvent and solute?

Q 10.

What are the physical states of dispersed phase and dispersion medium of a fog?

Q 11.

What is meant by a pure substance?

Q 12.

What are suspensions? Explain with an example.

Q 13.

To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293K. Find its concentration at this temperature.

Q 14.

How crystallization is better than evaporation?

Q 15.

What are the advantages of preparing solutions?

Q 16.

Why air is a mixture not a compound? Give reasons.

Q 17.

Name the elements are in liquid state at room temperature.

Q 18.

Based on the type of solvent, how solutions are classified?

Q 19.

Define mixture.

Q 20.

Based on the amount of solute in the given solution, how solutions are classified?

Q 21.

What are the properties of a colloid?

Q 22.

How many elements are there which are in gaseous state at room temperature?

Q 23.

List the points of differences between homogeneous and heterogeneous mixtures.

Q 24.

A good method to separate alum (phitkari) from impure samples is
(a) Filtration
(b) Sedimentaion
(c) Crystallization
(d) Sublimation

Q 25.

What are the physical states of dispersed phase and dispersion medium of a cloud?

Q 26.

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

Q 27.

How will you separate iron pins from sand ?

Q 28.

What are the various methods to express concentration of a solution?

Q 29.

What is meant by Solubility?

Q 30.

Name the technique to separate
(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt

Q 31.

State three reasons why you think air is a mixture and water is a compound.

Q 32.

Name the process you would use to separate a mixture of two miscible liquids (like acetone and water).

Q 33.

Name a metal which is soft and a non-metal which is hard.

Q 34.

Fill in the following blanks with suitable words :
(a) An element is made up of only one kind of...........atoms
(b)Brine is a..........whereas alcohol is a.......
(c) Brass is an alloy which is considered a..........
(d) The three important metalloids are.............and...........
(e) The elements which are sonorous are called...............

Q 35.

What is difference between colloids and suspensions ?

Q 36.

21.5 g of sodium chloride dissolves in 60 g of water at 25°C. Calculate the solut water at that temperature.

Q 37.

(a) What is a physical change ? Give two examples of physical changes.
(b) What is a chemical change ? Give two examples of chemical changes.

Q 38.

What is Chromatography?

Q 39.

Name a metal :
(a) which can be easily cut with a knife
(b) which forms amalgams
©which has not fixed shape
(d) which has a low melting point
(e) which is yellow in colour

Q 40.

Which technique can be used to detect and identify traces of poison present in the stomach wash of a person ?

Q 41.

How would you separate a mixture of sugar and salt ?

Q 42.

What are non-aqueous solutions?

Q 43.

Is air a mixture or a compound ? Give three reasons for your answer.

Q 44.

How are sol, solution and suspension different from each other?

Q 45.

Which of the following is a mixture ?Salt, Air, Water, Alum, Sugar

Q 46.

Name the process you would use to separate a mixture of water and alcohol.

Q 47.

(a) Name the process by which all the dye can be recovered from black ink.
(b) Name the process by which the various dyes' (coloured materials) present in black ink can be separated.

Q 48.

A 5 per cent sugar solution means that:
(a)5 g of sugar is dissolved in 95 g of water.
(b)5 g of sugar is dissolved in 100 g of water.
Choose the correct answer.

Q 49.

Choose one term from the following which includes the other three :
aerosol,
emulsion,
colloid,
sol

Q 50.

(a) What is meant by a solution ? Give two examples of solutions.
(b)What is a suspension ? Give two examples of suspensions.
(c)