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सी.आई.एस.सी.ई.आईसीएसई ICSE Class 8

Explain the following type of chemical reaction, giving two examples for it: Decomposition reaction

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प्रश्न

Explain the following type of chemical reaction, giving two examples for it:

Decomposition reaction

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उत्तर

A reaction in which a compound breaks up due to heat application into two or more simple substances is called a decomposition reaction.

\[\ce{AB->[heat] A + B}\]
Examples:

  1. Mercuric oxide when heated, decomposes to form two elements mercury and oxygen
    \[\ce{2HgO_{(s)}->[heat] 2Hg_{(s)} + O2_{(g)}}\]
  2. CaCO3 when heated decomposes to calcium oxide and carbon dioxide.
    \[\ce{CaCO3 ->[heat] CaO + CO2}\]
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अध्याय 6: Chemical Reactions - Exercise 2 [पृष्ठ ८६]

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एस पी सिंग Concise Chemistry [English] Class 8 ICSE
अध्याय 6 Chemical Reactions
Exercise 2 | Q 4.2 | पृष्ठ ८६

संबंधित प्रश्न

What does one mean by exothermic reaction? Give example.


A solid substance P which is very hard is used in the construction of many buildings, especially flooring. When substance P is heated strongly, it decomposes to form another solid Q and a gas R is given out. Solid Q reacts with water with the release of a lot of heat to form a substance S. When gas R is passed into a clear solution of substance S, then a white precipitate of substance T is formed. The substance T has the same chemical composition as starting substance P.

  1. What is substance P? Write its common name as well as chemical formula.
  2. What is substance Q?
  3. What is gas R?
  4. What is substance S? What is its clear solution known as?
  5. What is substance T? Name any two natural forms in which substance T occurs in nature.

What type of reaction is represented by the following equation?

\[\ce{CaCO3 -> CaO + CO2}\]


What type of reaction is represented by the following equation?

\[\ce{2FeSO4 -> Fe2O3 + SO2 + SO3}\]


What type of chemical reaction takes place when limestone is heated?


What type of chemical reaction is represented by the following equation?

\[\ce{X -> Y + Z}\]


When a green iron salt is heated strongly, its colour finally changes to brown and odour of burning sulphur is given out.

  1. Name the iron salt.
  2. Name the type of reaction that takes place during the heating of iron salt.
  3. Write a chemical equation for the reaction involved.

What does one mean by endothermic reaction? Give example.


Study the following figure and answer questions. 

a) After heating Calcium carbonate, which gas is formed in a test tube?
b) When we pass this gas through limewater what change, did you observe?
c) Write down the chemical reaction showing the product formation after heating the Calcium carbonate.

 


(a) Design an activity to demonstrate the decomposition reaction of lead nitrate.

(b) Draw labelled diagram of the experimental set-up. List two main observations.

(c) Write balanced chemical equation for the reaction stating the physical state of the reactant and the products.


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