Question

Worksheet
Answer the following 10x2-20
1. What is Mixture?
2. What are Isotopes?
3. Define Atomic number and Mass number
4. Define Isobars
5. What is combination Reaction?
6. Mention the rules to write the Electronic
configuration
7. What are emulsions?
8. Define Brownian movement
9. Is air is a pure substance or mixture?
Justify
10. List any two characteristics of pure
Substance?
Answer in Detail. 1x5-5
1.Write the difference between mixtures and Compounds​

Answer 1

1. mixture is an impure substance which contains two or many substances in any proportion by mass. Eg: sand is a mixture of many impurities in any proportion.

2. isotopes are the atoms of same element having same atomic number but different mass number. Eg: Hydrogen has three isotopes(Protium, Deuterium, Tritium).

3. atomic number is the number of protons or electrons present in the atom of an element. It is denoted by Z. Eg: The atomic number of calcium is 40.

mass number is the total number of protons a d neutrons present in the nucleus of an element. It is denoted by A.

4. Isobars are the atoms of differdifdelements having same mass number but different atomic number.

5. a reaction in which two or more compounds react to form a single compound is called combination reaction.

6. 2n^2 is the rule to write the Electronic Configuration.

2 x 1^2 = 2

2 x 2^2 = 8

2 x 3^2 = 18

..

..

..

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7. when a liquid is dropped into another liquid which is inmiscible is called emulsion. Eg: water and oil.

8. the random of particles in solid, liquid or gas is called brownian motion. Robert Brown discovered it.

9. Air is a mixture. Because air contains many substances like dust, gases, impurities, water vapour etc in any proportion of mass.

10. a. It has definite properties and definite composition.

b. Elements and compounds are pure substances .

Answer in detail:

MIXTURES:

Mixture is an impure substance.

Mixture is not represented by a specific chemical formula.

They donot have a definite proportion.

It is heterogeneous.

Eg: sand.

COMPOUND:

Compound is a pure substance.

It is represented by a specific chemical formula.

They must have definite proportion.

It is homogeneous.

Eg: salt, water.

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