Advertisements
Advertisements
Question
Write one equation for decomposition reactions where energy is supplied in the form of heat.
Advertisements
Solution
- \[\ce{\underset{Zinc carbonate}{ZnCO3_{(s)}} ->[\Delta]\underset{Zinc oxide}{ZnO_{(s)}} + \underset{Carbon dioxide}{CO2_{(g)}}}\]
- \[\ce{\underset{(Limestone)}{\underset{Calcium carbonate}{CaCO3_{(s)}}} ->[heat] \underset{(Lime)}{\underset{Calcium oxide}{CaO_{(s)}}} + \underset{Carbon dioxide}{CO2_{(g)}}}\]
- \[\ce{\underset{(Green colour)}{\underset{Ferrous sulphate}{2FeSO4_{(s)}}} ->[heat] \underset{(Brown colour)}{\underset{Ferric oxide}{Fe2O3_{(s)}}} + \underset{dioxide}{\underset{Sulphur}{SO2_{(g)}}} + \underset{trioxide}{\underset{Sulphur}{SO3_{(g)}}}}\]
- \[\ce{\underset{Potassium chlorate}{2KClO3_{(s)}} ->[Heat][(Decomposition)] \underset{Potassium chloride}{2KCl_{(s)}} + \underset{Oxygen}{3O2_{(g)}}}\]
- \[\ce{\underset{(Colourless)}{\underset{Lead nitrate}{2Pb(NO3)2_{(s)}}} ->[Heat][(Decomposition)] \underset{(Yellow)}{2PbO_{(s)}} + \underset{(Brown fumes)}{\underset{Nitrogen dioxide}{4NO2_{(g)}}} + \underset{Oxygen}{O2_{(g)}}}\]
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.
Taking into consideration the relationship in the first pair, complete the second pair
2H2 + O2 → 2H2O :Combination Reaction :: 2HgO → 2Hg + O2:_________
Give one example of a decomposition reaction which is carried out with electricity
What type of reaction is represented by the following equation?
\[\ce{NH4Cl -> NH3 + HCl}\]
What type of chemical reaction is represented by the following equation?
X → Y + Z
Two metals X and Y form the salts XSO4 and Y2SO4, respectively. The solution of salt XSO4 is blue in colour whereas that of Y2SO4 is colourless. When barium chloride solution is added to XSO4 solution, then a white precipitate Z is formed alongwith a salt which turns the solution green. And when barium chloride solution is added to Y2SO4 solution, then the same white precipitate Z is formed alongwith colourless common salt solution.
(a) What could the metals X and Y be?
(b) Write the name and formula of salt XSO4.
(c) Write the name and formula of salt Y2SO4.
(d) What is the name and formula of white precipitate Z?
(e) Write the name and formula of the salt which turns the solution green in the first case.
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{Zn_{(s)} + H2SO4 -> ZnSO4_{(s)} + H2_{(g)}}\]
(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.
A student wants to study a decomposition reaction by taking ferrous sulphate crystals. Write two precautions he must observe while performing the experiment.
Answer the following question.
2 g of silver chloride is taken in a china dish and the china dish is placed in sunlight for some time. What will be your observation in this case? Write the chemical reaction involved in the form of a balanced chemical equation. Identify the type of chemical reaction.
Give a balanced equation for –
A thermal decomposition reaction involving heat on limestone [calcium carbonate]
Explain the reaction given in the figure.
Electrolysis is type of ______ reaction.
Which among the following statement(s) is (are) true?
Exposure of silver chloride to sunlight for a long duration turns grey due to
(i) the formation of silver by decomposition of silver chloride.
(ii) sublimation of silver chloride.
(iii) decomposition of chlorine gas from silver chloride.
(iv) oxidation of silver chloride.
The reaction of calcium carbonate, with freshly prepared lime water, is shown below:
Answer the questions with the help of a diagram:
- What type of reaction does calcium carbonate undergoes?
- What change in colour is observed in lime?
- Write the chemical equation.
These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Silver bromide decomposition is used in black and white photography.
Reason: Light provides energy for this exothermic reaction.
What is observed when silver chloride is exposed to sunlight? Give the type of reaction involved.
When lead nitrate is heated strongly in a boiling tube, two gases are liberated and a solid residue is left behind in the test tube.
- Name the type of chemical reaction and define it.
- Write the name and formula of the coloured gas liberated.
- Write the balanced chemical equation for the reaction.
- Name the residue left in the test tube and state the method of testing its nature (acidic/basic).
