Pure Substance, Mixture and Compound Class-6th Goyal Brothers Chemistry Solutions ch-2 unit-2

Pure Substance, Mixture and Compound Class-6th Goyal Brothers Chemistry Solutions Chapter-2 (unit-2). We Provide Step by Step Answers of Objective, True False , Fill in the blanks, Match the following , Study Questions of Chapter- 2, Elements, Compounds and Mixtures, Unit-2 (Pure Substance, Mixture and Compound). Visit official Website  CISCE  for detail information about ICSE Board Class-6.

Pure Substance, Mixture and Compound Class-6th

Goyal Brothers Chemistry Solutions Chapter-2 unit-2

Board ICSE
Class 6th
Subject Chemistry
Book Name Goyal Brothers
Theme-2 Elements, Compounds and Mixtures
Unit-2 Pure Substance, Mixture and Compound
Topic Solution of exercise questions
Session 2023-24

OBJECTIVE TYPE QUESTIONS

Chemistry Solutions Chapter-2 unit-2

A. Fill in the blanks :

  1. A mixture in which its constituents are not distributed evenly is called a _heterogeneous_ mixture.
  2. A common salt solution is a _homogeneous_ mixture.
  3. Ferrous sulphide is a _compound_ of iron and sulphur.
  4. _Water_ is a compound of hydrogen and oxygen.
  5. The constituents of a _mixture_ retain their individual chemical and physical properties.

B. Statement given below are incorrect. write the correct correct statement:

1. A powerful magnet separates iron from the compound iron sulphide.

Correct Statement: A powerful magnet separates iron from the compound iron sulphide.

2. Air is a compound of mainly oxygen and nitrogen gas.

Correct Statement: Air is a compound of mainly oxygen and nitrogen gas.

3. Sugar solution is an example of a heterogeneous mixture.

Correct Statement: Sugar solution is an example of a homogeneous mixture.

4. Milk is a pure substance.

Correct Statement: Milk is not a pure substance.

5. In a mixture of iron and sulphur, the particles of iron can be removed by dissolving sulphur in water.

Correct Statement: In a mixture of iron and sulphur, the particles of iron cannot be removed by dissolving sulphur in water.

C. Match the statement in Column A with those in Column B:

Column A

Column B

1. A homogeneous material which contains particles of one kind and has definite properties.

(a) Homogeneous mixture.

2. Two or more substance are mixed together in any proportion, such that they do not undergo any chemical change.

(b) Heterogeneous mixture

3. A mixture whose contents are mixed uniformly.

(c) Alloy

4. A homogeneous mixture of molten metals.

(d) Pure substance

5. A mixture whose contents are not mixed uniformly.

(e) Mixture

Answer:

Column A

ColumnB

1. A homogeneous material which contains particles of one kind and has definite properties.

(d) Pure substance

2. Two or more substance are mixed together in any proportion, such that they do not undergo any chemical change.

(e) Mixture

3. A mixture whose contents are mixed uniformly.

(a) Homogeneous mixture.

4. A homogeneous mixture of molten metals.

(c) Alloy

5. A mixture whose contents are not mixed uniformly.

(b) Heterogeneous mixture

D. Write ‘True’ or ‘False’ for the following statements :

  1. A common salt solution is a homogeneous mixture. [T]
  2. A pure substance is homogeneous material which contains particles of one kind only. [T]
  3. Sugar solution is a heterogeneous mixture. [F]
  4. Alloy is a mixture of two or more gases. [F]
  5. Iron sulphide is an element. [F]

E. Tick (√) the most appropriate answer.

1. The constituents of a mixture are present in :

(a) Fixed ratio

(b) any ratio

(c) in the ratio of 4:1

(d) none of these

Ans: (b) any ratio

2. The constituent of a compound can be separated by :

(a) physical means only

(b) chemical means only

(c) both physical and chemical means

(d) none of these

Ans: (b) chemical means only

3. Milk is a :

(a) pure substance

(b) element

(c) mixture

(d) a chemical compound

Ans: (c) mixture

4. A mixture of sand in water is an example of :

(a) Heterogeneous mixture

(b) Homogeneous mixture

(c)Homogeneous solution

(d) Chemical compound

Ans: (a) Heterogeneous mixture

5. When a mixture is formed :

(a) A physical change takes place

(b) A chemical change takes place

(c) Both physical and chemical changes take place

(d) none of these

Ans: (a) A physical change takes place

STUDY QUESTIONS

Question 1.

(a) What do you understand by the terms

(i) pure substance (ii) mixture ?

Answer:

(i) Pure substances are defined as substances that are made of only one type of atom or only one type of molecule.

(ii) A mixture is formed when atoms or molecules of the same or different particles combine with each other physically in any ratio.

(b) Name (i) four elements (ii) four compounds, which can be termed as pure substance.

Answer: Four elements which can be termed as pure substance are carbon, oxygen, hydrogen and iron.

Four compounds which can be termed as pure substance are water (H2O), carbon dioxide (CO2), methane (CH4), sodium nitrate (NaNO3).

Question 2. Identify the pure substances and mixture from the following list :

(a) Solid common salt – Pure Substance

(b) Milk – Impure substance

(c) Air – Impure substance

(d) Oxygen – Pure Substance

(e) fruit juice – Impure substance

(f) brass – Impure substance

(g) copper sulphate crystals – Pure Substance

(h) distilled water – Pure Substance

(i) sugar solution – Impure substance

(j) honey – Impure substance

(k) ice cream – Impure substance

(l) iron sulphate – Pure Substance

Question 3. By giving one example for each, define:

(a) Heterogeneous mixture : A heterogeneous mixture refers to the non-uniform mixture of various substances. It can be separated by physical methods. Constituent particles can be seen by naked eyes.

Example- milk, sugar solution in water, oil etc.

(b) Homogeneous mixture: It is a gaseous, liquid or solid mixture that has the same proportions of its components throughout a given sample. It is uniform in composition throughout.

Example- Air, Sugar water etc

Question 4. State four characteristics of a mixture.

Answer: Four characteristics of a mixture are:-

  • The mixture has no fixed composition.
  • To form mixture energy is neither produced nor evolved.
  • The mixture has no fixed melting points and boiling points.
  • Mixture retains the properties of its components.

Question 5. Identify (a) homogeneous mixture and (b) heterogeneous mixture from the following list.

(i) common salt solution

(ii) a mixture of salt and Sulphur

(iii) milk

(iv) brass

(v) air

(vi) fruit juice

(vii) cooked vegetables of peas and onions

Answer: Homogeneous mixture = common salt solution, brass, air, fruit juice.

Heterogeneous mixture =  a mixture of salt and sulphur, milk, cooked vegetables of peas and onions.

Question 6. By giving two reasons prove that a powder containing iron and sulphur is a mixture, but iron sulphide is a compound.

Answer: Using a magnet the iron powder in the mixture can be separated from the sulphur powder in the mixture. But when we heat the mixture of iron filings and sulphur, the product we get is iron sulphide. Iron sulphide is a compound. It is not a mixture.

Question 7. By giving two reasons prove that air is an example of a mixture.

Answer: Air is a mixture and not a compound because of the following reasons: Air can be separated into its constituents such as oxygen, nitrogen etc. by fractional distillation of liquid air. Air shows the properties of all the gases present in it.

Question 8. By giving two reasons prove water is an example of a compound.

Answers: Water is a compound because it is composed of two different elements, hydrogen and oxygen which cannot be separated by physical methods. They can be separated only by chemical methods

Question 9. Give four main difference between a mixture and a compound.

Answers: Difference between a mixture and a compound are

Mixture Compound
1. Mixtures are impure substances 1. Compounds are pure substances.
2. These are may be homogeneous or heterogeneous in nature. 2. These are always homogeneous in nature
3. A mixture has no fixed composition, 3. A compound has a fixed composition
4. Components can be separated by  simple physical methods.  4. Components can be separated only by complex chemical process

— : end of Pure Substance, Mixture and Compound Class-6th Goyal Brothers Chemistry Solutions:–-

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