# Chemistry Class 11 NCERT Solutions: Chapter 5 States of Matter Part 1

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Q: 1. What will be the minimum pressure required to compress 500 of air at 1 bar to 200 at

Answer:

Given,

Initial pressure,

Initial volume,

Final volume,

Since the temperature remains constant, the final pressure can be calculated using Boyle’s law.

According to Boyle’s law,

Therefore, the minimum pressure required is 2.5 bar.

Q: 2. A vessel of 120 mL capacity contains a certain amount of gas at and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at What would be its pressure?

Answer:

Initial pressure,

Initial volume,

Final volume,

Since the temperature remains constant, the final pressure can be calculated using Boyle’s law.

According to Boyle’s law,

Therefore, the pressure would be 0.8 bar.

Q: 3. Using the equation of state show that at a given temperature density of a gas is proportional to gas pressure.

Answer:

The equation of state is given by,

Where,

From equation (i) we have,

Replacing n with we have

Where,

But,

Thus, from equation (ii), we have

Molar mass (M) of a gas is always constant and therefore, at constant temperature

(T),

Hence, at a given temperature, the density (d) of gas is proportional to its pressure (p)