Cbse Class 10 Science Chapter 1 Important Questions - Chemical Reactions And Equations

CBSE Class 10 Science Chapter 1 focuses on Chemical Reactions and Equations, explaining how substances interact to form new products, balanced equations, and types of reactions like combination, decomposition, displacement, and redox reactions. Understanding these concepts is essential for solving important questions in CBSE Class 10 Board exams.

Class 10 Science Chapter 1 Important Questions - Chemical Reactions And Equations

Here are 50 important questions on Class 10 Science Chemical Reactions And Equations

1. Why should a magnesium ribbon be cleaned before burning in air?
2. Write the balanced equation for the reaction of hydrogen and chlorine to form hydrogen chloride.
3. What is the balanced equation for the reaction between barium chloride and aluminum sulfate?
4. How does sodium react with water? Provide the balanced equation.
5. Write a balanced chemical equation with state symbols for the reaction of barium chloride and sodium sulfate.
6. What happens when sodium hydroxide solution reacts with hydrochloric acid?
7. What is the substance 'X' used for whitewashing, and what is its formula?
8. Describe the reaction of calcium oxide with water.
9. Why is the amount of gas collected in one test tube during electrolysis of water double that in another?
10. What color change occurs when an iron nail is dipped in copper sulfate solution, and why does this happen?
11. Provide an example of a double displacement reaction.
12. In the reaction 4Na+O2→2Na2O4Na+O2​→2Na2​O, identify the oxidized and reduced substances.
13. What type of reaction occurs when Fe2O3+2Al→Al2O3+2FeFe2​O3​+2Al→Al2​O3​+2Fe?
14. What products are formed when dilute hydrochloric acid is added to iron filings?
15. Define a balanced chemical equation and explain why balancing is necessary.
16. Translate the statement "Hydrogen gas combines with nitrogen to form ammonia" into a chemical equation.
17. Balance the equation HNO3+Ca(OH)2→Ca(NO3)2+H2OHNO3​+Ca(OH)2​→Ca(NO3​)2​+H2​O.
18. What are exothermic reactions? Provide an example.
19. Explain what endothermic reactions are, with an example.
20. Why is respiration considered an exothermic reaction?
21. Describe the difference between combination reactions and decomposition reactions.
22. Write an equation for a decomposition reaction where heat is supplied.
23. Explain the concept of displacement reactions with an example.
24. What is a precipitation reaction? Provide an example.
25. Define oxidation in terms of gain or loss of oxygen, and give examples.
26. Define reduction in terms of gain or loss of oxygen, and give examples.
27. Identify a shiny brown element that turns black upon heating in air, and name the compound formed.
28. Why do we apply paint on iron articles?
29. Explain why oils and fats are flushed with nitrogen during packaging.
30. Define corrosion and provide an example.
31. What is rancidity, and how can it be prevented?
32. Describe how to balance chemical equations effectively.
33. What happens during electrolysis of water, and what gases are produced?
34. Describe how to identify whether a reaction is exothermic or endothermic based on temperature changes.
35. Explain how to determine if a reaction is a displacement or double displacement reaction based on reactants and products.
36. What role does reactivity play in displacement reactions?
37. Provide an example of a chemical equation that represents a combustion reaction.
38. How do you identify reactants and products in a chemical equation?
39. Explain the significance of state symbols in chemical equations.
40. Discuss why certain metals corrode more quickly than others.
41. Describe how temperature affects the rate of chemical reactions.
42. Explain what happens at the molecular level during a chemical reaction.
43. How can you tell if a chemical change has occurred?
44. What safety precautions should be taken when conducting experiments involving chemical reactions?
45. Discuss how catalysts affect chemical reactions.
46. Describe what happens during the neutralization process between acids and bases.
47. Explain how to experimentally determine if a gas produced in a reaction is hydrogen or oxygen.
48. Discuss why some reactions are classified as redox reactions.
49. How can you use indicators to determine pH changes during acid-base reactions?
50. Explain how to write net ionic equations for precipitation reactions.

These questions cover various aspects of chemical reactions, equations, types of reactions in the chapter

‍

Chemical Reactions and Equations Short Notes:

Explore concise and informative Chemical Reactions and Equations short notes to understand key concepts and enhance your preparation for CBSE Class 10 Science exams.

1. Chemical Reactions

Definition: A process where one or more substances (reactants) are transformed into new substances (products) with different properties.

Example:  2H₂ + O₂ = 2H₂O .

Indicators of a Chemical Reaction:

- Change in state.

- Change in color.

- Evolution of gas.

- Change in temperature.

- Formation of a precipitate.

‍

2. Chemical Equation

• Definition: A symbolic representation of a chemical reaction using formulas of reactants and products.

• Example:  Na + Cl_2 \rightarrow NaCl .

• Balanced Chemical Equation:

• Follows the Law of Conservation of Mass: Mass of reactants = Mass of products.

• Example:  Zn + H_2SO_4 \rightarrow ZnSO_4 + H_2 .

• Steps to Balance an Equation:

• Write the unbalanced equation.

• Count the number of atoms of each element on both sides.

• Use coefficients to balance atoms.

• Verify the equation is balanced.

‍

3. Types of Chemical Reactions

1. Combination Reaction:

• Two or more reactants combine to form a single product.

• Example:  2H_2 + O_2 \rightarrow 2H_2O .

2. Decomposition Reaction:

• A single compound breaks into two or more simpler substances.

• Example:  2H_2O_2 \rightarrow 2H_2O + O_2 .

3. Displacement Reaction:

• A more reactive element displaces a less reactive one from its compound.

• Example:  Zn + CuSO_4 \rightarrow ZnSO_4 + Cu .

4. Double Displacement Reaction:

• Exchange of ions between two compounds.

• Example:  NaCl + AgNO_3 \rightarrow AgCl (\text{ppt}) + NaNO_3 .

5. Redox Reaction:

• Oxidation and reduction occur simultaneously.

• Example:  2Mg + O_2 \rightarrow 2MgO  (oxidation of Mg, reduction of O).

‍

4. Exothermic and Endothermic Reactions

• Exothermic Reaction: Releases energy in the form of heat.

• Example:  CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O + \text{Heat} .

• Endothermic Reaction: Absorbs energy from surroundings.

• Example:  CaCO_3 \rightarrow CaO + CO_2  (requires heat).

‍

5. Precipitation Reactions

• Definition: Reaction in which an insoluble solid (precipitate) forms.

• Example:  BaCl_2 + Na_2SO_4 \rightarrow BaSO_4 (\text{ppt}) + 2NaCl .

‍

6. Oxidation and Reduction

• Oxidation:

• Gain of oxygen or loss of electrons.

• Example:  2Mg + O_2 \rightarrow 2MgO .

• Reduction:

• Loss of oxygen or gain of electrons.

• Example:  CuO + H_2 \rightarrow Cu + H_2O .

Conclusion

The chapter Chemical Reactions and Equations is a fundamental part of the Class 10 Science syllabus, explaining how substances interact and transform through various types of reactions.

Understanding the balancing of equations and the significance of reaction types is essential for mastering the subject. To excel, students can refer to Class 10 Science study materials, focus on CBSE Class 10 Science Chapter 1 important questions, and practice with Class 10 Science sample papers.

Comprehensive Chemical Reactions and Equations notes will help solidify concepts and ensure better preparation for exams.

Other Chapters:

Chapter 1 Chemical Reactions And Equations

Chapter 2 Acids, Bases, And Salts

Chapter 3 Metals And Non-Metals

Chapter 4 Carbon and its compounds

Chapter 5 Life Processes

Chapter 6 Control And Coordination

Chapter 7 How Do Organisms Reproduce?

Chapter 8 Heredity And Evolution

Chapter 9 Light – Reflection And Refraction

Chapter 10 The Human Eye And The Colourful World

Chapter 11 Electricity

Chapter 12 Magnetic Effects Of Electric Current

Chapter 13 Our Environment