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.

What is the general name of the process by which tea-leaves are separated from prepared tea ?

Q 2.

What are the properties of a colloid?

Q 3.

Classify the following as physical or chemical changes :
(i) Cooking of food

Q 4.

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

Q 5.

Name one pair of liquids which can be separated by using a separating funnel.

Q 6.

What is saturated solution? Explain with an example.

Q 7.

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

Q 8.

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 9.

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

Q 10.

What is meant by solute and solvent?

Q 11.

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

Q 12.

Name the process you would use to separate ammonium chloride from a mixture of sodium chloride and ammonium chloride.

Q 13.

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

Q 14.

Who gave the first explanatory definition of 'element'?

Q 15.

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

Q 16.

(a) What is meant by (i) elements (ii) compounds, and (iii) mixtures ? Write down the names of two elements,two compounds and two mixtures.
(b) Classify the following into elements,
compounds and mixtures :
Marble,
Air,
Gold,
Brass,
Sand,
Diamond,
Graphite,
Petroleum,
Common salt,
Sea-water,
Chalk

Q 17.

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

Q 18.

Name the source from which nitrogen and oxygen are obtained on a large scale.

Q 19.

What are non-aqueous solutions?

Q 20.

What is an unsaturated solution?

Q 21.

What is Chromatography?

Q 22.

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 23.

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

Q 24.

What is the general name of the materials which contain at least two pure substances and show the properties of their constituents ?

Q 25.

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

Q 26.

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

Q 27.

Name the property of any one of the components which can be used for separating the following mixture : Salt and Camphor

Q 28.

Name the apparatus you would use to separate oil from water.

Q 29.

What are the characteristics exhibited by a pure substance?

Q 30.

What is meant by a pure substance?

Q 31.

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

Q 32.

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

Q 33.

What are aqueous solutions?

Q 34.

When we open the cap of a cola drink (or any carbonated beverage), why does excess of bubbles come out?

Q 35.

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

Q 36.

What are suspensions? Explain with an example.

Q 37.

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

Q 38.

What are different ways to separate solid mixtures?

Q 39.

What is an emulsion? Give examples

Q 40.

State whether the following statement is true or false : Milk is a pure substance.

Q 41.

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

Q 42.

What are pure substances ? Give two examples of pure substances.

Q 43.

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 44.

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

Q 45.

Describe sieving method.

Q 46.

Who used the term 'element' first time?

Q 47.

What is meant by saying that non-metals are brittle ?

Q 48.

The properties of the product are different from those of the constituents. State whether this statement best describes an element, a compound or a mixture.

Q 49.

Give two reasons for supposing that water is a compound and not a mixture.

Q 50.

What is the concentration of a solution which contains 16 g of urea in 120 g of solution ?