1.chemical Reactions And Equations.docx

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QUESTIONS Name different types of reactions. Define combination reaction by giving a balanced chemical equation. Define decomposition reaction by writing a balanced chemical equation for it. Define displacement reaction. Why should a magnesium ribbon be cleaned before burning in air? What is corrosion? What is rancidity? What is rusting? What conditions are necessary for corrosion? How can we prevent articles from rusting? Write a balanced chemical equation for it : Iron + water Iron oxide + hydrogen gas Write a balanced chemical equation for it : Carbon dioxide + water glucose + oxygen Write a balanced chemical equation for it : Zinc + sulphuric acid Zinc sulphate + hydrogen gas Write a balanced chemical equation for it : Methane + oxygen carbon dioxide and water Write a balanced chemical equation for it : Sodium sulphate + barium chloride barium sulphate + sodium chloride What is the difference between combination and decomposition reaction? A solution of a substance ‘X’ is used for white washing. (i) Name the substance ‘X’ and write its formula. (ii) Write the reaction of the substance ‘X’ named in (i) above with water. (i)What are redox reactions? (ii)Name the substance oxidized and reduced in the following equation. ZnO + C → Zn +CO Respiration is considered an exothermic reaction? Explain. A shiny brown coloured element ‘X’ on heating in air becomes black in colour.Name the element ‘X’ and the black coloured compound formed. What do you mean by a precipitation reaction? Explain by giving examples. In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved. How can we prevent food items from rancidity? Oil and fat containing food items are flushed with nitrogen. Why? Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity. (i)Why are decomposition reactions called the opposite of combination reactions? (ii)Write equations for these reactions.

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Why does the colour of copper sulphate solution change when an iron nail is dipped in it? The amount of gas collected in one of the test tubes during electrolysis of water double of the amount collected in the other? Explain the reason. A brown coloured substance kept in the open changes in colour to green after a few days.Name the substance and the process behind it.

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