Question

Classify the following into elements, compounds, and mixtures. (i) Pure sand (ii) Air (iii) Ammonia gas (iv) Ice (v) Glass (vi) Cao.

Answer 1

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1. Pure sand - mixture
2. Air - Compound
3. Ammonia gas -
4. Ice - Compound
5. Glass - Mixture
6. CaO (Oxocalcium) - Compound

→ Element - An element is the basic form of the matter that cannot be broken down into substance by chemical reactions.

• Example - Iron, Copper, Silver, Oxygen, Nitrogen and hydrogen etc.

→ Mixture - A mixture contains more than one substances.

• Example - Sea water, Air, soil etc.

→ Types of mixture -

1) Homogeneous mixture

• Example - Air, Drinking water.

2) Heterogeneous mixture

• Example - Oil in water and stone in pulses.

→ Compound - A compound is a substance that is formed by the combination of two or more element in a fixed ratio by mass.

• Example - Water, Acid, Sodium chloride, Methane etc.

Answer 2

Answer:

1.Pure Sand is a mixture

2.Air is a compound

3.Ammonia Gas is a compound

4.Ice is a compound

5.Glass is a mixture

Explanation:

1.Pure sand has many particles mixed with it. It has minerals, sand particles and etc.

2.Air has many sub-gases. It has Oxygen, CarbonDioxide, Argon, Nitrogen, Neon, Helium, etc.

3.Ammonia Gas is a chemical compound composed of one nitrogen atom and three hydrogen atoms. So, it can be classified as a compound

4.Ice is a compound because ice is frozen water. Water is a compound made of 2 Hydrogen atom and 1 Oxygen atom. So, it is a compound.

5.Glass is the homogenous mixture of the silicates of various alkaline metals of non-crystalline and transparent or less transparent substances. It is manufactured by the composition of various substances like silica, bleaching powder, oxides of alkaline metals, calcium oxide (lime) etc.