Which of the following quantities is zero on an average for the molecules of an ideal gas in equilibrium?

1. We know that momentum is a vector quantity defined as product of mass and velocity of particle in motion.


2. According to kinetic theory of ideal gas, molecules of gas are in random motion.


3. Due to this random motion, velocity on an average will be zero. This is because velocity is a vector quantity, having both direction and magnitude.


4. Because velocity have direction, in random motion all the components of velocity will cancel out each other and it will be zero on an average.


5. Thus, average momentum will also be zero.

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