The document defines key chemistry concepts including elements, compounds, and mixtures. It provides examples of each. It also discusses hard and soft water, explaining that hard water does not lather easily with soap due to calcium and magnesium ions, and how each type of hardness can be removed. The document defines alloys as mixtures of metals that impart special properties, and amalgams as alloys containing mercury. It concludes by listing several common chemical substances and their chemical names and compositions.

1. Chemistry
Element: It cannot be split into simpler substances, e.g., iron, sulphur, oxygen, gold. There are about 106
elements.
Compound: It can be split into simpler substances and is formed by the union of two or more elements
in definite proportions by weight, e.g.
1. Water can be split into hydrogen and oxygen.
2. Iron sulphide is split into iron and sulphur.
3. Chalk is made of calcium, carbon and oxygen.
4. Carbondixoide is made up of carbon and oxygen.
Mixture: It is one in which two or more substances are mixed together in any ratio without altering their
properties.
1. Sand and salt
2. Sugar and water
3. Air is a mixture of nitrogen and oxygen
4. Gun-powder is a mixture of nitre, charcoal and sulphur
Hard and Soft Water: Hard water is that water which does not produce lather with soap easily. Soft
water produces lather with soap very easily.
There is two kinds of hardness: -
(i) Temporary
(ii) Permanent.
 Temporary is due to bicarbonates of calcium and magnesium. Can be removed by
(i) boiling, (ii) addition of lime.
 Permanent is due to the sulphates and chlorides of calcium and magnesium.
Permanent hardness can be removed by (I) addition of washing soda, or (ii) by
distillation.
Alloy: Is a mixture of two or more metals in a certain proportion. Alloys are made to impart
certain special properties to the metals in question. For example, stainless steel is made
using Iron, Manganese, Carbon etc. to give it high strength, elasticity etc which is not found
in Iron.
Amalgam: any alloy containing Mercury as an essential component is known as amalgam.

2. Chemical Names of substances:
Chemical Name of the Substance
Substance Chemical Name Composition
Green vitriol Iron sulphate Iron, sulphur and oxygen
Litharge Lead monoxide Lead and oxygen
White vitriol Zinc sulphate Zinc sulphur and oxygen
Caustic lotion Silver nitrate Silver, nitrogen and oxygen
Candy fluid Potassium permanganate Potassium, manganese and oxygen
Blue vitriol Copper sulphate Copper, sulphur and oxygen
Kansi (Alloy) Bronze Copper, zinc, tin
Pital (Alloy) Brass Copper, zinc
Shora or nitre Potassium nitrate Potassium, nitrogen and oxygen
Caustic potash Potassium hydroxide Potassium, hydrogen and oxygen
Chile saltpeter Sodium nitrate Sodium, nitrogen and oxygen
Baking soda Sodium bicarbonate Sodium, hydrogen, carbon and oxygen
Washing soda Sodium carbonate Sodium, carbon and oxygen
Common salt Sodium chloride Sodium and chlorine
Caustic soda Sodium hydroxide Sodium, hydrogen and oxygen
Gluber’s salt Sodium sulphate Sodium, sulphur and oxygen
Iron pyrites Iron sulphide Iron and sulphur
Galena Lead sulphide Lead and sulphur
Gyspum Calcium sulphate Calcium, sulphur and oxygen
Epsom Magnesium sulphate Magnesium, sulphur and oxygen
Aspirin Acetyl Salicylic Acid
Vinegar Acetic Acid (Glacial) Carbon, Hydrogen, Oxygen
Bleaching Powder Calcium Oxychloride Calcium, Oxygen, Chlorine
Marble Calcium Carbonate Calcium, Carbon, Oxygen
Rust Ferric Hydroxide Iron, Hydrogen, Oxygen
Plaster of Paris Hydrated Calcium Sulphate Calcium, Sulphur, Hydrogen, Oxygen