Previous Year Questions - Chemical Reactions and Equations

Chemical reactions and equations is an important topic in Class 10 Science. To score well in the exam, it is essential to solve previous year questions. Here are some important questions from previous years that will help you in preparing for the exam.

1. What is a chemical reaction? Explain with an example.

A chemical reaction is a process in which one or more substances are transformed into one or more new substances. For example, the reaction between iron and sulfur to form iron sulfide is a chemical reaction.

2. What is meant by a balanced chemical equation?

A balanced chemical equation has an equal number of atoms of each element on both the reactant and product sides of the equation. This means that the law of conservation of mass is obeyed.

3. What is the difference between a physical and chemical change?

A physical change is a change in which no new substance is formed. For example, melting of ice is a physical change. In contrast, a chemical change is a change in which one or more new substances are formed. For example, burning of paper is a chemical change.

4. What are the different types of chemical reactions?

The different types of chemical reactions are:

- Combination reactions
- Decomposition reactions
- Displacement reactions
- Double displacement reactions
- Redox reactions

5. What is meant by an exothermic reaction? Give an example.

An exothermic reaction is a chemical reaction in which energy is released in the form of heat. For example, the reaction between magnesium and oxygen to form magnesium oxide is an exothermic reaction.

6. What is meant by a precipitation reaction?

A precipitation reaction is a type of double displacement reaction in which an insoluble product (precipitate) is formed. For example, the reaction between silver nitrate and sodium chloride to form silver chloride and sodium nitrate is a precipitation reaction.

In conclusion, solving previous year questions is an effective way to prepare for the Class 10 Science exam. By understanding the concepts and practicing questions, you can score well in the exam.

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