Chemical Reactions

Questions based on matter and its properties: Q1. what is matter Ans:Matter is anything which occupies space and has mass. eg-pen,paper,water droplet,air etc Q2.Explain an activity to show that particles of matter have space between them Ans: Q3. What are the properties of matter? Ans: The properties of matter are as follows: 1. Matter is made up of particles. 2. Particles of matter are very very small. 3. Particles of matter have space between them. 4. Particles of matter move continuously. Q4.What is diffusion?  Ans: It is defined as the movement of particles of matter from higher concentration to lower concentration. eg- when we burn incense stick its gaseous particles mix with the particles of air on their own and as a result we get the fragrance in the whole room. Q5.How does temperature effect the rate of diffusion? Ans:The particles of matter possess kinetic energy and when we increase the temperature the kinetic energy also increases and a...

Matter Anything that occupies space and has mass is considered to be matter. Eg- chalk,pen,table,air etc. Properties of Matter 1. Matter is made up of particles 2. Particles of matter are very very small 3. Particles of matter have space between them. 4. Particles of matter are continuously moving. Activities to explain the properties of matter: Activity 1.1 1.Take half beaker filled with water and mark the level of water. 2. Dissolve salt or sugar with the help of glass rod. Observation: The volume of water of the water remains same.This can be explained by assuming that the particles of water have spaces between them. Explanation When salt or sugar is dissolved in water its crystals separate into very fine particles. 20 particles of sugar go into the spaces between the various particles of water due to which there is no change in volume of water. Activity 1.2 Take two to three crystals of potassium permanganate and dissolve them in 100 ml of water. Take o...

Decomposition reactions These are the reactions in which a single reactant breaks down to form 2 or more products by the absorbing energy in the form of light,heat and electricity. TYPES OF DECOMPOSITION 1. Thermal decomposition reactions 2. Photo decomposition reactions 3. Electro decomposition reactions THERMAL DECOMPOSITION REACTION These are the chemical reactions in which this substance splits up into two or more products by the absorption of heat energy. Activity (A) Heating ferrous sulphate crystals in a dry test tube. OBSERVATION  1 . The green colour of ferrous sulphate crystals first changes to White and then become brown coloured solid which is ferric oxide. 2. Gas having the smell of burning sulphur comes out of the tube due to evolution of Sulphur dioxide and sulphur trioxide gases . Chemical equation ACTIVITY(B) Heating of lead nitrate in dry test tube OBSERVATION  1. Brown fumes of Nitrogen dioxide gas are evolved which fil...

Combination Reactions  These are the reactions in which two or more reactants combined together to form a single product. Activity 1.3 Reaction between water and calcium oxide(quick lime) OBSERVATION Calcium oxide reacts vigorously with water to produce slaked lime(calcium hydroxide) Reaction mixture becomes warm because heat has released during the reaction Equation A solution of slaked lime that is calcium oxide,i.e calcium hydroxide  is used for whitewashing. This calcium hydroxide react slowly with carbon dioxide in air to form a thin layer of calcium carbonate on the wall after 2 to 3 days of white washing and give the the shiny appearance to the walls. EXOTHERMIC REACTIONS  These are the reactions in which heat energy is released along with the product Combination reactions are exothermic reactions. Examples 1.     2. Respiration is also considered to be an exothermic process. During digestion food is broken down into simpler substances. For example rice,p...

Chemical reaction  It is a process in which one or more reactants are converted into products. In chemical reactions the nature and identity of the initial substance have changed. Chemical reaction is an Irreversible process. Example 1. Milk left at room temperature during summer becomes curdled. 2. Grapes after fermentation changes to Wine.  3. Food is cooked So in all these three  examples we can see that the initial properties of the substance that is milk,grapes,raw vegetables etc changes and these changes can not be reversed. Activity 1.1 Burning of magnesium ribbon Observation 1. Magnesium ribbon burns with the dazzling flame 2. Changes to White powder of magnesium oxide. 3.Energy is released. Activity 1.2 Reaction between Lead Nitrate and potassium iodide  OBSERVATION; Precipitated of lead iodide are formed which are white in colour. Add caption