Composition of Matter Science Notes

Composition of Matter Science Notes

Important Points:

Characteristics of States of matter

Physical state of matter Fluidity/
Rigidity/
Plasticity/
Elasticity
Volume Shapes Compressibility Intermolecular force Distance between particles
Solid Rigid/
plastic/
elastic
Definite Definite Negligible Strong Minimum
Liquid Fluid Definite Indefinite Very small Moderate Moderate
Gaseous Fluid Indefinite Indefinite Very high Very weak Very large

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Characteristics of Element, Compound and mixture

Composition of Matter Science Notes 1
Composition of Matter Science Notes 2

Water

A compound: Pure water is a compound formed by chemical combination of the elements hydrogen and oxygen. Whatever may be the source of water, the proportion of its constituent elements oxygen and hydrogen by weight is always 8:1.

Hydrogen is an inflammable gas while oxygen gas supports combustion. However, the compound water formed by chemical combination of the gaseous elements hydrogen and oxygen is a liquid. It is neither inflammable nor does it support combustion. On the contrary it helps to extinguish fire.

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Milk

A mixture: Milk is a mixture of water, lactose, fats, proteins and a few more natural substances. The proportion of various ingredients of milk is different as per its source. The proportion of fats in cow milk is 3-5%, while it is 6-9% in buffalow milk.

The ingredient water is naturally present in large proportion in milk. Therefore milk exists in liquid state. The sweetness of milk is due to the ingredient called lactose. In other words, the properties of the constituent substances are retained in milk.

Types of elements:

Composition of Matter Science Notes 3

Types of compounds

Composition of Matter Science Notes 4

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Types of mixtures

Composition of Matter Science Notes 5

→ Solution: A homogenous mixture of two or more substances is called solution.
→ Solvent: The component of a solution which is present in the largest proportion is called solvent.
→ Solute: The other component of a solution which is present in less proportion than the solvent is called solute.

→ All the particles of a solid that stay together (or are in the same container) constitute a single phase. (E.g., a heap of stones.) A liquid substance along with all the soluble substances dissolved in it together constitute a single phase. (E.g. sea water)

→ A liquid or all its drops present together or in the same container constitute a single phase. (E.g., rain drops) The liquids present together or in the same container, but not mixed with each other, constitute separate phase. (E.g., oil and water) All the gases present together constitute a single phase. (E.g., air)

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Types of solutions

Composition of Matter Science Notes 6

→ Suspension: The heterogenous mixture of a liquid and a solid is called a suspension E.g., sand in water.
→ Colloid: The heterogenous in which the diameter of particles is around 10– 5 m is called a colloid. E.g. milk, blood.

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Molecular formula

→ Molecular formula indicates the number of atom of each of the constituent elements present in one molecule of a compound.

Compound Water
Molecular formula H20
Constituent elements H
O
Number of atoms of constituent elements 2
1

Science Notes

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