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Chemical reactions and equations class 10 worksheet



In this page we have chemical reactions and equations class 10 worksheet with answers . Hope you like them and do not forget to like and share the page.
a. Multiple Choice Questions
b. Fill in the blanks
c. True and False
d. Very Short answer type
e. Short Answer type
f. Long answer questions

Multiple Choice Questions

1. What type of reaction is \(2H_2 + O_2 \rightarrow 2H_2O\)?
(a) Combination reaction
(b) Decomposition reaction
(c) Displacement reaction
(d) Double displacement reaction

2. In the reaction \(2HgO \rightarrow 2Hg + O_2\), what type of reaction is this?
(a) Combination reaction
(b) Decomposition reaction
(c) Displacement reaction
(d) Double displacement reaction

3. In the reaction \(Zn + CuSO_4 \rightarrow ZnSO_4 + Cu\), what is being displaced?
(a) Zinc
(b) Copper
(c) Sulphate
(d) Water

4.What type of reaction is characterized by heat being released?
(a) Exothermic
(b) Endothermic
(c) Oxidation
(d) Reduction

5. In a double displacement reaction, what happens?
(a) A more reactive element displaces a less reactive element from its compound
(b) Two elements swap places in two different compounds
(c) A compound breaks down into its elements
(d) Two elements combine to form a compound

6.In the redox reaction
MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2
(a) MnO2 is reduced to MnCl2 & HCl is oxidized to H2O
(b) MnO2 is reduced to MnCl2 & HCl is oxidized to Cl2
(c) MnO2 is oxidized to MnCl2 & HCl is reduced to Cl2
(d) MnO2 is oxidized to MnCl2 & HCl is reduced to H2O

Answer

1(a) , 2(b) ,3(b) , 4(a), 5(b)
6 (b)
MnO2 is reduced to MnCl2 & HCl is oxidized to Cl


Fill in the blanks:-

1.Addition of hydrogen in a substance in a reaction is known as___________ reaction.
2.In a ________ reaction two or more substances combine to form a new single substance.
3.Unbalanced reactions are also known as _________
4.Reactions in which heat is given out along with the products are called _________- reactions.
5.Reactions in which energy is absorbed are known as _________ reactions.
6.When as element displaces another element from its compound, a ________ reaction occurs.
7.Those reactions, in which two compounds react by an exchange of ions to form two new compounds, are called ________ reactions
8.Precipitation reactions produce __________ salts.
9.Reduction is the _________ of oxygen or gain of hydrogen.
10.The digestion of food in the body is an example of ____________ reaction.
11.The addition of oxygen to a substance is called __________.
12.When calcium carbonate is heated, it decomposes to give___________ and _________.

Answer

1.reduction
2.Combination
3.skeletal
4.Exothermic
5.Endothermic
6.Displacement
7.Double displacement
8.Insoluble
9.Loss
10.Decomposition reaction
11.Oxidation
12.CaO(s) and CO2 (g)


True/ False:-

1.The number of atoms of each element is conserved in any chemical reaction.
2.Oxidation is the loss of electrons from a substance.
3.Reduction is the gain of electrons by a substance.
4.A complete chemical equation represents the reactants, products and their physical states symbolically.
5.A magnesium ribbon burns with a dazzling flame in air (oxygen) and changes into a white substance, magnesium oxide.
6.Rusting is a double decomposition reaction.
7.The reaction between nitrogen and hydrogen to give ammonia is an example of a combination reaction.
8.Action of heat on ferrous sulphate is an example of decomposition reaction.
9.The formation of Na+ and CI- ions from sodium and chlorine is an example of a redox reaction.

Answer

1. TRUE
2. TRUE
3. TRUE
4. TRUE
5. TRUE
6. FALSE
7. TRUE
8. TRUE
9. TRUE



Very Short Answer Questions:-

Question 1. Write a chemical equation when magnesium metal reacts with aqueous hydrochloric acid to produce a solution of magnesium chloride and hydrogen gas.
Question 2. Can a combination reaction be redox reaction.
Question 3. Why do we apply paint on iron articles?
Question 4. What are the different types of reactions?
Question 5. What is a decomposition reaction ? Give example.
Question 6. Define displacement reaction.
Question 7. What happens when sodium reacts with water?
Question 8. Write the chemical equation and name the reaction when a solution of sodium chloride is mixed with a solution of silver nitrate and a white precipitate of silver chloride is formed.
Question 9. Why does the color of copper sulphate solution change, when an iron nail is dipped in it?
Question 10. Why is photosynthesis considered as an endothermic reaction?
Question 11. Potassium chlorate (KCIO3) on heating forms potassium chloride and oxygen. Write a balanced equation for this reaction.
Question 12. Give an example of a chemical reaction characterized the change in temperature.
Question 13. What type of chemical reactions take place when:
(a)Limestone is heating?
(b)A magnesium wire is burnt in air?
(c)Electricity is passed through water?
(d)Ammonia and hydrogen chloride are mixed?
(e)Silver bromide is exposed to sunlight?
Question 14. To balance a chemical equation, can we change the formula of either reactants or products?
Question 15. Why should a magnesium ribbon be cleaned before burning in air?
Question 16. If an of the following reactions occurs spontaneously, write the balanced net ionic equation. If not, write no reaction&
(a)Pb + Zn2+ _____ Pb2+ + Zn
(b)Fe + H+ _____Fe2+ + H2
(c)Cu + Ag+ _____ Cu2+ + Ag
(d)Cr + Zn2+ _____Cr2+ + Zn
Question 17. Nickel (II) nitrate is prepared by heating nickel metal with liquid dinitrogen tetroxide. In addition to the nitrate, gaseous nitrogen monoxide is formed. Write the balanced equation.
Question 18. Why is the amount of gas collected in one of the test tubes in electrolysis of water double of the amount collected in the other? Name this gas.
Question 19. Write a balanced chemical equation with state symbols for the following reactions:-
i.Solution of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.
ii.Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.

Answer

(1)
Mg + 2HCL -> MgCl2 + H2

(2) Yes,a combination reaction can be a redox reaction.
In a combination reaction two elements are combined to make a single product.
2H2+O2=2H2O (water's formula)
In this reaction there is reduction of oxygen as there is transfer of electrons from hydrogen to oxygen and there is also oxidation of hydrogen as there is acceptance of electrons by oxygen from hydrogen.Oxygen is the oxidizing agent and hydrogen is the reducing agent.
(3) To prevent it from Corrosion
(4) Combination reactions
Decomposition reaction
Displacement reactions
Double displacement reactions
Oxidation and Reduction reactions

(5) Those reactions in which a compound splits up into two or more simpler substances are known as decomposition reactions.

(6) Those reactions, in which one element takes the place of another element in a compound, are known as displacement reactions.
cuSO4 + Zn -> ZnSO4 + Cu
(7) Sodium can react with cold water as it is an extremely reactive metal; when it does,
2Na + H2O --> H2 + Na2O (Sodium Oxide)
The reaction is very vigorous and exothermic.

(8) NaCl + AgNO3 -> AgCl + NaNO3
Double displacement and precipitation reaction

(9)When an iron nail dipped in the copper sulphate solution than iron displaces copper from the copper sulphate because iron is more reactive than copper. Therefore the color of the copper sulphate solution changes.

(10) Photosynthesis is considered an endothermic reaction because energy in the form of sunlight is absorbed by the green plants.

(11) 2KCIO3 -> 2KCL + 3O2

(19)
(i) BaCl2 + Na2SO4 -> BaSO4 (ii) NaOH + HCL -> NaCl + H2O



Short Answer Questions:-

Question 1. State what type of reaction the following are:
(a) Splitting of water into hydrogen and oxygen
(b)burning of hydrogen in air
(c) Action of iron with copper sulphate solution
(d) Action of  heat on calcium carbonate
(e) Treating silver nitrate with hydrochloric acid
Question 2. When ice is exposed to air, it melts to form water and when hydrogen in burnt in air, it forms water. How do these changes differ?
Question 3. Blue Copper Nitrate crystals turns black when heated. Explain.
Question 4. When chlorine is passed through potassium iodine solution containing chloroform, purple color is observed. Explain.
Question 5.When silver nitrate is added to seawater, a white precipitate is formed. Explain.

Long Answer Questions:-

Question 1. Give the characteristic tests for the following gases
(a) CO2
(b) SO2
(c) O2
(d) H2

Answer

Here are the characteristic tests for the following gases
(a) CO2 (Carbon Dioxide): When carbon dioxide is passed through lime water (calcium hydroxide), it turns the lime water milky due to the formation of calcium carbonate.
Ca(OH)2(aq) + CO2(gas) -> CaCO3(s) + H2O(l)
(b) SO2 (Sulphur Dioxide): Sulphur dioxide can be tested by passing the gas through a solution of acidified potassium dichromate(VI). The orange solution gets decolorized as sulphur dioxide reduces orange potassium dichromate(VI) to green chromium(III) ions.This is a redox reaction
K2Cr2O7(aq) + H2SO4 + 3SO2 -> K2SO4 + Cr2(SO4)3 + H2O
(c) O2 (Oxygen): A common test for oxygen is the glowing splint test. In this test, a glowing splint is inserted into a test tube containing the gas. If the splint rekindles and starts to burn brightly, the gas is oxygen.
(d) H2 (Hydrogen): A common test for hydrogen is the pop test. In this test, a lit splint is brought near the mouth of the test tube containing the gas. If the gas is hydrogen, it will ignite with a 'pop' sound.


Question 2. What happens when a piece of (a) zinc metal is added to copper sulphate solution? (b) aluminium metal is added to dilute hydrochloric acid? (c) silver metal is added to copper sulphate solution? Also, write the balanced chemical equation if the reactionoccurs Question 3. Mention three ways by which a usual chemical equation can be made more informative.

Answer

A usual chemical equation can be made more informative in the following ways:
(a)Writing Symbols of Physical States: To make a chemical equation more informative, the physical states of the reactants and products are mentioned along with their chemical formulae. The gaseous, liquid, aqueous, and solid states of reactants and products are represented by the notations (g), (l), (aq), and (s), respectively. The word aqueous (aq) is written if the reactant or product is present as a solution in water.
(b) Balancing the Chemical Equation: A chemical equation is balanced so that the numbers of atoms of each type involved in a chemical reaction are the same on the reactant and product sides of the equation. This is in accordance with the law of conservation of mass, which states that mass can neither be created nor destroyed in a chemical reaction.
(c) Including Reaction Conditions: Sometimes the reaction conditions, such as temperature, pressure, catalyst, etc., for the reaction are indicated above and/or below the arrow in the equation. This provides additional information about the conditions under which the reaction occurs.This included heat given or heat obtained i,e whether the reaction is exothermic or endothermic


Question 4. What is meant by skeletal chemical equation? What does it represent? Using the equation for electrolytic decomposition of water, differentiate between a skeletal chemical equation and a balanced chemical equation.

Summary

This chemical reactions and equations class 10 worksheet with answers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.


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