HELP ASAP WILL MARK BRAINLIEST!! Copper reacts with sulfur to form copper (I) sulfide, according to the balanced equation below. 2Cu S → Cu2S Given that there are 40. 2 g Cu and 14. 1 g S, complete the steps below to determine the limiting and excess reactants in the last question. How many moles are in 40. 2 g Cu? mol Cu How many moles are in 14. 1 g S? mol S.