Chemistry

Is Matter Around Us Pure?

Question:

What are the differences and similarities between concentration and solubility?

Answer:

  1. Concentration is amount of solute dissolved in a unit quantity (mass or volume) of a solution. While solubility is the maximum amount of the solute that can be dissolved in a given amount of the solvent.
  2. Concentration is expressed as percent by weight or volume, mole fraction, molarity etc. Solubility is the ability of a solute to dissolve in a solvent at given temperature and pressure. It is expressed as grams/litre or moles/litre.
  3. Based on concentration, a solution can be saturated, unsaturated or supersaturated. Based on solubility, the solutes are soluble or insoluble, miscible or immiscible.
  4. (Similarity) Both depends on temperature.
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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 are the differences and similarities between concentration and solubility?

Q 4.

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

Q 5.

What are the characteristics exhibited by a pure substance?

Q 6.

Name two properties of a substance to check its purity?

Q 7.

What are the properties of suspensions?

Q 8.

What factors affect the solubility of solvent and solute?

Q 9.

What is meant by a pure substance?

Q 10.

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

Q 11.

What are suspensions? Explain with an example.

Q 12.

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

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.

Define mixture.

Q 16.

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

Q 17.

What are the advantages of preparing solutions?

Q 18.

Name the elements are in liquid state at room temperature.

Q 19.

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

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.

What are the characteristics of mixture?

Q 27.

What is meant by Solubility?

Q 28.

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

Q 29.

(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 30.

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

Q 31.

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

Q 32.

Name one pair of substances whose mixture can be separated completely by distillation.

Q 33.

How will you separate iron pins from sand ?

Q 34.

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

Q 35.

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

Q 36.

Give examples of liquids that are
(i) completely miscible
(ii) partially miscible
(iii) practically immiscible

Q 37.

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

Q 38.

Winnowing works on what property?

Q 39.

Name the following :
(a) a lustrous liquid metal.
(b) a liquid non-metal
(c) a metal which can be cut with a knife
(d) a non-metal which is good conductor of electricity.
(e) an element which melts when kept on the palm.
(f) the best conductor of heat.

Q 40.

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

Q 41.

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

Q 42.

Name a non-metal which is a good conductor of electricity.

Q 43.

Which of the following will show Tyndall effect ? Why ?
(a) Salt solution
(b) Starch solution
(c)Milk

Q 44.

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

Q 45.

State whether the following statements are true or false :
(a) Alcohol can be separated from a mixture of alcohol and water by a separating funnel.
(b) Salt and water can be recovered from an aqueous salt solution by the process of evaporation.

Q 46.

Name the process by which the various gases of the air are separated.

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.

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

Q 49.

What difference in the properties of common salt and sand would enable you to separate a mixture of these two substances ?

Q 50.

How would you separate a mixture of sugar and salt ?