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Questions
What is a decomposition reaction?
What is meant by decomposition reaction?
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Solution
A decomposition reaction is a chemical reaction in which a single compound breaks down to simpler products. It is the opposite of a combination reaction.
RELATED QUESTIONS
Why is the amount of gas collected in one of the test tubes in the following Activity double of the amount collected in the other? Name this gas.
- Take a plastic mug. Drill two holes at its base and fit rubber stoppers in these holes. Insert carbon electrodes in these rubber stoppers as shown in the following Fig.
- Connect these electrodes to a 6 volt battery.
- Fill the mug with water such that the electrodes are immersed. Add a few drops of dilute sulphuric acid to the water.
- Take two test tubes filled with water and invert them over the two carbon electrodes.
- Switch on the current and leave the apparatus undisturbed for some time.
- You will observe the formation of bubbles at both the electrodes. These bubbles displace water in the test tubes.
- Is the volume of the gas collected the same in both the test tubes?
• Once the test tubes are filled with the respective gases, remove them carefully. - Test these gases one by one by bringing a burning candle close to the mouth of the test tubes.
Caution: This step must be performed carefully by the teacher.
- What happens in each case?
- Which gas is present in each test tube?
What does one mean by exothermic reaction? Give example.
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Write one equation for decomposition reactions where energy is supplied in the form of heat.
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Rewrite the following statements by selecting the correct options:
\[\ce{CaCO3 ->[\Delta] CaO + CO2 ^}\] is a __________ reaction.
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.
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(c) What is gas R?
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(b) What is compound B?
(c) What is gas C?
(d) What do you think is the black substance X? What is its function?
(e) What is the general name of substances like X?
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Give one example of a decomposition reaction which is carried out by applying heat.
Give one example of a decomposition reaction which is carried out with electricity.
What type of reaction is represented by the following equation?
\[\ce{CaCO3 -> CaCO + CO2}\]
What type of chemical reaction take place when electricity is passed through water?
What type of chemical reaction is represented by the following equation?
X → Y + Z
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Name the product formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change?
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\[\ce{Zn_{(s)} + H2SO4 -> ZnSO4_{(s)} + H2_{(g)}}\]
How will you obtain Nitrogen dioxide from lead nitrate.
Also give balanced equations for the reactions
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What do you mean by redox reaction ? Explain with the help of an example.
What does one mean by endothermic reaction? Give example.
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Study the following figure and answer questions.
a) After heating Calcium carbonate, which gas is formed in a test tube?
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c) Write down the chemical reaction showing the product formation after heating the Calcium carbonate.
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Give a balanced equation for –
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Give a balanced equation for –
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Complete the statement by filling in the blank with the correct word:
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Give a balanced equation for the following type of reaction:
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Explain the reaction given in the figure.
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Electrolysis is type of ______ reaction.
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Balance the following chemical equation and identify the type of chemical reaction.
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- Write a balanced chemical equation of the reaction.
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- What change in colour is observed in lime?
- Write the chemical equation.
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- Identify 'A' and 'B'
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Write the molecular formula of calcium carbonate.
Write one equation for decomposition reactions where energy is supplied in the form of electricity.
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