Alannah added a strip of zinc to a beaker containing a solution of copper sulfate, as shown in the photo. She expected to observe the immediate
formation of solid copper in the beaker but saw no evidence of a reaction.
Alannah predicted that the reaction was happening too slowly to observe.
Which statement could best explain this result?

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.

a