The pressure the gas exert the walls of the container will decrease because the gas particles hit the wall of the container

The statement is false. The pressure of a gas do not decrease as the gas molecules hit the walls of the container. According to the Kinetic Molecular Theory, collisions of the gas molecules or with the walls of the container are perfectly elastic. This means that energy is not lost as the molecules collide with each other or with the walls of the container.

Adozen is 12, and your needing to calculate the weight of one medium egg, so i would do 21/12=1.75 per egg, and check your answer by doing 1.75 * 12= 21 : ) : ): ): ): ) i hoped i