If a gas is expanded at constant temperature:a)The pressure decreaseb)The kinetic energy of the molecules remains the samec)The kinetic energy of the molecules decreasesd)The number of molecules of the gas increase.Correct answer is option 'A,B'. Can you explain this answer?

Question

Answer

**Expansion of a Gas at Constant Temperature**

When a gas is expanded at constant temperature, there are several changes that occur in the system. Let's examine each option provided in the question and explain why the correct answers are option 'A' and 'B'.

a) The pressure decreases:
When a gas is expanded, its volume increases. According to Boyle's Law, at constant temperature, the pressure and volume of a gas are inversely proportional. This means that as the volume increases, the pressure decreases. So, option 'a' is correct.

b) The kinetic energy of the molecules remains the same:
The kinetic energy of gas molecules is directly proportional to the temperature of the gas. The temperature remains constant in this scenario, so the kinetic energy of the gas molecules remains the same. Therefore, option 'b' is correct.

c) The kinetic energy of the molecules decreases:
As mentioned before, the temperature remains constant during the expansion. The kinetic energy of gas molecules is directly related to the temperature. Since the temperature is constant, the kinetic energy of the gas molecules does not change. Therefore, option 'c' is incorrect.

d) The number of molecules of the gas increases:
The expansion of a gas at constant temperature does not involve any change in the number of gas molecules. It only affects the volume, pressure, and kinetic energy of the gas. Therefore, option 'd' is incorrect.

In summary, when a gas is expanded at constant temperature, the pressure decreases due to the inverse relationship between pressure and volume according to Boyle's Law. The kinetic energy of the gas molecules remains constant because the temperature is held constant. There is no change in the number of gas molecules during this process.

Answer

As temperature remain constant so kinetic energy will remain same so optt C is wrong and no of molecules will remain same so option D is wrong.

Due to expansion the pressure decreases.
So option A and B is correct

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