Question

Holiday homework :-

Class : 1

1) What is chemical reaction?
2) What is balanced chemical equation? Why should chemical equations be balanced?
3) What is the difference between exothermic and endothermic reaction? Explain with example.
4) What is combination and decomposition reaction? Explain with example.
5) What is displacement and double displacement reaction? Explain with example.
6) What is redox reaction? Give example and identify oxidised and rudeced substance in the reaction.
7) Write short note on :-
a) Corrosion
b) Rancidity
8) How can you prevent any substance from corrosion and rancidity write the methods?

Answer 1

Answer:

Foolish

Explanation:

All do by yourself

Answer 2

Explanation:

1. A process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction, is called a chemical reaction.

2. A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side. For example :- Zn + HCl ---> ZnCl2 + H2 ...

3. Endothermic Reaction

•The energy is absorbed from the surround into the reaction. For example : making ice cubes melting ice cubes

Exothermic Reaction

•The energy is released from the system to its environment. For example : combustion.

4. Combination Reaction

•When two or more reactants combine with each other to form a new product it is called as combination reaction. Combination reaction is also known as synthesis reaction. For example hydrogen gets combined with chlorine to from hydro-chloride.

Decombination Reaction

• Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions. Example : Reaction of iron nails with copper sulphate solution.

5. Displacement Reaction

•Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions. Example : Reaction of iron nails with copper sulphate solution.

Double Displacement Reaction

•Double displacement Reaction - definition. A double displacement reaction is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products. For example, Na2S+2HCl→2NaCl+H2S.

6. Redox Reaction

•Redox Reactions: Redox reactions are a chemical reaction is which oxidation and reduction take place simultaneously. Example: (1) During this reaction, barium sulphate loses oxygen and is hence reduced. At the same time, Carbon gains oxygen and is therefore oxidised.

7. Corrosion: It is the process in which metals are slowly eaten up by the action of air moisture or chemicals. ...

Rancidity: When the substance containing oils and fats are exposed to air they get oxidised and become rancid due to which their smell, taste and colour change. This process is known as rancidity.

8. Rancidity can be prevented using the following methods:

•Adding antioxidants (substances which prevent oxidation) to food.

•Storing food in airtight containers to slow the process of rancidification.

•Refrigerating food also helps to slow down rancidification.

•Replacing oxygen in the containers with another gas.