Question

3.Identify each of the following reactions also write balanced chemical equations of each
a. A reaction in which reaction mixture becomes warm
b.A reaction in which insoluble substance formed(2)

Your answer

5.An object 2 cm tall is placed on the axis of a concave mirror of focal length 5 cm at a distance 10 cm from mirror .find the nature ,position &size of the image is formed (2)

Your answer



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Answer 1

The reaction mixture becomes warm:

In an exothermic reaction, the reaction mixture becomes warm because heat is released.

U(Object distance)= -15 cm

F(Focal Length, Concave Mirror is negative) = -10 cm

Using Mirror Formula,

1/F = 1/U + 1/V

1/-10 = 1/-15 +1/V

-1/10 = -1/15 +1/V

1/15 - 1/10 = 1/V

(2-3)/30 = 1/V

-1/30 = 1/V

V = -30

Magnification = -V/U ( - Image Distance / Object Distance)

Magnification = -(-30)/-15

M= 30/-15

M = -2

So the nature of the image will be Real and Inverted, position of the Image would be -30 cm, Size of the image would be twice the object (enlarged).

Common examples of exothermic reactions are:

photosynthesis, respiration, nuclear fission, combustion reaction, neutralization reaction, the reaction between water and strong acids, anhydrous salts etc. Reactants react with oxygen in the air upon heating to produce the products along with energy.

Reactants \rightarrow Product + Energy

Equation:

Combustion of natural gas:

An insoluble substance is formed in reactions involving double displacement and precipitation reactions.

When aqueous potassium chloride reacts with aqueous silver nitrate solution, double displacement takes place forming an insoluble precipitate of silver chloride and aqueous potassium nitrate.