Need !
which two objects have stored energy?

a ball rolling on the ground
a small rock sitting on top of a big rock
a stretched rubber band
a stone lying on the ground

The balanced chemical equation for this lab is: 3cucl2(aq) + 2al(s) 3cu(s) + 2alcl3(aq) if 10.5 g copper chloride react with 12.4 g aluminum, what is the limiting reactant?

What reaction is taking place? 02 + c3h8 = h20 + co2

An electron moved from shell n = 2 to shell n = 1. what most likely happened during the transition? a fraction of a photon was added. a photon of energy was absorbed. a fraction of a photon was removed. a photon of energy was released.