Question

7. What are the following called?
(a) A reaction in which heat or light is evolved
(b) A reaction in which heat or light is absorbed
(c) The type of reaction in which two or more substances add up to form a new product
(d) The type of reaction in which a substance is broken down into simpler substances
(e) The type of reaction in which an element displaces another
2-what would you observe in the following cases
(a)carbon dioxide is passed through lime water
(b) An ignited magnesium ribbon is placed in steam
(c) A mixture of hydrogen and oxygen is Lit.
(d) An iron knife is placed in a solution of copper(II)sulphate.
3- give balanced chemical equations representing the following reactions.
(a) on being heated with chlorine iron form iron (III) chloride
(b) carbon dioxide dissolves in water to form carbonic acid
(c) when burnt in oxygen magnesium forms magnesium oxide
(d) Hydrogen reacts with chlorine in sunlight to give hydrogen chloride
(e) when heated with Sulphur iron form iron(II) sulphide.
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Answer 1

Answer:

7.(a)exothermic reaction.

(b)Endothermic reactions.

(c)synthesis reaction.

(d)decomposition reaction/

(e)A single replacement reaction, sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound. The starting materials are always pure elements, such as a pure zinc metal or hydrogen gas, plus an aqueous compound.

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