Minerals and Energy Resources Minerals and their Mode of Occurrence •Minerals in homogenous naturally occurring inorganic substances with a definable internal structure. •Found in rocks beneath the earth's surface in the form of Compounds. •Possess a solid crystal structure.Having a definite chemical composition comprising one or more elements. •Can be identified by their physical and chemical properties. •Different appearances and occurrence in various form, in a wide range of colours, hardness forms lustre and density.As all minerals are formed formed from a certain combination of elements which depends upon the chemical and physical conditions under which the mineral forms.The geologists use these properties to categorise minerals. Important Of Minerals: • Everything we use, eat and drink has minerals. • Economic development of people or nation can be vastly accelerated by the presence of valuable minerals in the countries. • Make our life Comfortable and Convenient. • They are

Source of Energy Notes •Energy comes in different forms and one form can be converted into another. •A source of energy is one which provide adequate amount of energy in a convenient form over a long period of time. Need of energy: • For making Food. • For lightening . • For transport . • For  running machines. • For industrial activities and agricultural work. Qualities of a Good Source of energy 1. which would do a large amount of work per unit mass. 2. Cheap and easily available. 3. Easy to store and transport. 4. Safe to handle and use. 5. Does not cause environmental pollution. Fuels: The materials which are burn to produce heat energy are known  as Fuels E.g wood, cool, LPG, Kerosence. Characteristics of a good fuel • High calorific value (give more heat per unit mass). • Burn without giving out any smoke or harmful gases. • Proper ignition temperature  • cheap and easily  available • Easy to handle , safe to transport. • Convenient to store. • Burn smoothly.     Sourc

chemical reactions and equations →The process in which new substances with new properties are formed from one or more substance is called chemical reaction. •The substances which take part in chemical reaction are called reactants. •The substances which are formed in a chemical reaction are called Products. Examples:- (I)Digestion of food (II)Respiration (III)Rusting of iron (IV)Burning of magnesium ribbon (V)Formation of curd Chemical reaction involves: •change in state  •change in colour •change in temperature •Evolution of gas →chemical Equation  •A chemical reation can be represented by chemical equation.It involves used of symbol of elements or chemical formula of reactants and product with mention of physical state. •The necessary conditions such as temperature, pressure or any catalyst should be written on arrow between reactant and products.eg magnesium is burnt in air to form magnesium oxide.                    Mg +o²→ Mgo balancing chemical equations • law of conservation of