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# If a gas expands at constant temperature, it indicates that:(a) Kinetic energy of the molecules decreases(b) pressure of the gas increases(c) kinetic energy of the molecules remains same(d) number of the molecules of gas increases

Last updated date: 29th May 2024
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Hint: Gas is a state of matter. There are various laws to explain the behaviour of gases under different conditions of temperature, pressure and volume such as Boyle’s Law, Charles Law, Gay-Lussac’s law and Avogadro Law.

Complete step by step solution:
We know that the ideal gas equation is \[PV=nRT\].
In the P is the pressure, V is the volume of the gas, n is the number of moles of gas involved. R is Rydberg constant and T is the temperature.
From this equation, we get to know that for a given mass of gas, at constant temperature, the pressure is inversely proportional to volume. So, at constant temperature, when the gas expands, the pressure decreases.
For average kinetic energy, the expression is\[\dfrac{3}{2}RT\], where R is the Reydberg Constant and T is the temperature. Therefore, at a constant temperature, the kinetic energy will also be the same.
\[KE=\dfrac{3}{2}RT\]
\[KE\propto T\]
Therefore, when gas expands at a constant temperature, pressure decreases as well as kinetic energy of the molecules will remain the same. Hence, correct options are (b) and (c).