Newton's third law of interaction, says that if one body exerts a force on a second body, the second body exerts a force equal in magnitude and opposite in direction on the first body. It's the law of action-reaction, and it helps to explain why you feel a jolt when you collide with another bumper car.
The moles of any substance are equal to the substance's mass divided by its molar mass. Therefore, in order to calculate the moles of copper, you would divide the reacted mass by 63.55