Experiment 7 each reaction used an excess or extra of the reagent needed to push copper through the cycle of reactions. why use an excess instead of just enough to react with the amount of copper used?

to accelerate the reaction

Explanation:

In the context, a reaction is used at an extra reagent that is needed to push the copper through its cycle in the reaction because using an extra amount of copper or excess amount speed up the reaction and the products are proportionately formed. The extra copper acts as the catalyst and boost the reaction speed accelerating to from its products.

there is none because earth is stationary and flat.