Distinguish between an exothermic and an endothermic reaction amongst the
following reactions. Identify exothermic and the endothermic reaction:-
(a) Heating coal in air to farm carbon dioxide.
(b) Heating lime stone in lime kiln to form quick lime
What is redox reaction? When a magnesium ribbon burnish/air with dazzling flame
and farms a white ash, is magnesium oxidized or reduced? Why?
(a) Explain the term "corrosion” with an example write a chemical equation to show
the process of corrosion in iron.
(b) Name any three objects which are gradually damaged by the corrosion of iron
and steel
A solution of KCl when mixed with AgNO3 forms an insoluble substance. Which
type of reaction is it and also write the chemical equation.
A white salt on heating decomposes to give brown fumes and a residue is left
behind
a) Name the salt
b) Write the chemical reaction involved.
What is precipitation reaction. Write a balanced chemical equation to show a
precipitation reaction.
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Answers
hi
1. Endothermic reaction- a reaction which requires/absorbs heat from the surroundings to proceed is called endothermic reaction. Exothermic reaction - a reaction which releases heat to the surroundings is called endothermic reaction.
2. Exothermic reaction is a reaction in which heat is evolved with the formation of product whereas in
Endothermic reaction heat is absorbed during the reaction .
1. Endothermic
2.Endothermic
3.The reaction in which one reactant gets oxidised and the other reactant gets reduced is called redox reaction. ii. When a magnesium ribbon burns in air with a dazzling flame and forms a white ash, magnesium gets oxidised to magnesium oxide.
a)Corrosion: It is the process in which metals are slowly eaten up by the action of air moisture or chemicals. For example rusting is a form of corrosion in which iron is eaten up by the action of air and moisture and a reddish brown coating of iron oxide is formed as shown in the following chemical reaction
b)when a metal is attacked by air or moisture that metal is said to have corroded and this whole process is termed as Corrosion. Eg- Green colour coating on copper
4Fe+3o2+2xH2o=2Fe2O3.2xH2o
4.A white salt on heating decomposes to give brown fumes and a residue is left behind
(1) name is the salt ,
(2) write the balanced chemical equation involved.
5.A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name. Precipitation reactions can help determine the presence of various ions in solution.
hope it helps (: