Chapter 1: Chemical Reactions and Equation

Question 1

What is a Chemical Reaction?

Answer 1

The reaction in which a new component is produced with new properties.

A chemical reaction has taken place when:

1. change in state
2. change in colour
3. evolution of a gas
4. change in temperature.

Question 2

What is a Reactant?

Answer 2

Reactants are the starting materials in a chemical reaction. These are the substances that undergo a change.

Question 3

What is a Product?

Answer 3

Products are the new substances formed as a result of the chemical reaction. They are what you end up with after the reaction is complete.

Question 4

Balanced Chemical Equations

Answer 4

The total mass of the elements present in the products of a chemical reaction has to be equal to the total mass of the elements present in the reactants. In other words, the number of atoms of each element remains the same, before and after a chemical reaction.

Question 5

Skeletal Chemical Equation

Answer 5

Skeletal equations are equations with simply the chemical formulas of the products and reactants, no mention of state, and no atom balancing on either side of the equation.

Question 6

Types Of Chemical Reactions

Answer 6

Combination Reaction
Decomposition Reaction
Displacement Reaction
Double Displacement Reaction
Oxidation and Reduction

Question 7

Combination Reaction

Answer 7

A chemical change in which two or more substances react to form a single new substance.

Question 8

Decomposition Reaction

Answer 8

A reaction in which a single compound breaks down to form two or more simpler substances.

Question 9

Displacement Reaction

Answer 9

A reaction in which a more reactive element displaces a less reactive element from an aqueous solution.

Question 10

Double Displacement Reaction

Answer 10

A reaction in which a gas, a solid precipitate, or a molecular compound forms from the apparent exchange of atoms or ions between two compounds.

Question 11

Oxidation

Answer 11

The reaction in which energy is utilized by the addition of oxygen and removal of hydrogen.

Question 12

Reduction

Answer 12

The reaction in which energy is released by the removal of oxygen and addition of hydrogen.

Question 13

Exothermic Reaction

Answer 13

Reaction in which heat is released along with formation of products.

Question 14

Endothermic Reaction

Answer 14

The reaction which require energy in the form of heat, light and electricity to break reactants.

Question 15

Thermal Decomposition

Answer 15

When reaction is carried out by heating.

Question 16

Electrolytic Decomposition

Answer 16

When decomposition is carried out by passing electricity.

Question 17

Photolytic Decomposition

Answer 17

When decomposition is carried out in presence of sunlight.

Question 18

Corrosion

Answer 18

When a metal is exposed to moisture, air, acid etc. for sometime, a layer of hydrated oxide is formed which weakens the metal.

Question 19

Rancidity

Answer 19

The oxidation of fats and oils when exposed to air.