MIXTURES AND PURE SUBSTANCES MADE BY SOUHARD SHARMA IX-E 4

DEFINITIONS MIXTURES- Mixtures are physical combinations of pure substances that have no definite or constant composition — the composition of a mixture varies according to who prepares the mixture. Mixtures are heterogeneous forms of matter. Mixtures are composed of variable proportions of molecules and atoms.

DEFINITIONS PURE SUBSTANCES- It has a definite and constant composition — like salt or sugar. A pure substance can be either an element or a compound, but the composition of a pure substance doesn’t vary. Some of the pure substances isolated from mixtures cannot be further broken down. Oxygen (O2) is an example.

PROPERTIES OF MIXTURES It can be separated into 2 or more substances by physical or mechanical means It displays the properties of the pure substances making it up Its composition can be varied by changing the proportion of pure substances making it up Heterogeneous substances, ones with non-uniform composition throughout the sample, are always mixtures

PROPERTIES OF PURE SUBSTANCES It can be separated into 2 or more substances by physical or mechanical means It is homogeneous, i.e, has uniform composition throughout the whole sample Its properties are constant throughout the whole sample Its properties do not depend on how it is prepared or purified It has constant chemical composition

Practical Examples

SHERBET SHERBET- A MIXTURE OF ROOH AHFZA, LEMON AND WATER

IDLI IDLI- A MIXTURE OF RICE, WATER, URAD DAL, COCONUT CHUTNEY ETC.

Water(not tap water) WATER LIKE RAINWATER(NOT TAP WATER, IT CONTAINS SALT) IS A PURE SUBSTANCE.

(BREAKFAST) EGG, BREAD AND MILK THE GIVEN BREAKFAST IS A MIXTURE OF FATS AND WATER(MILK), CARBOHYDRATES AND YEAST(BREAD), PROTEIN AND YOLK(EGG), TOMATO AND WATER (TOMATO SAUCE).

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