Astudent spots an unknown sample on a tlc plate. after developing the plate in a 50: 50 mixture of hexane/ethyl acetate, the student sees a single spot with an rf of 0.40. does this indicate the unknown sample is a pure compound? what else could the student do to verify whether the sample is pure or a mixture?

Which of the following is the best explanation why some reactions appear to stop before all the reactants are converted to products? the reaction goes to completion. the reaction reaches equilibrium and the products stop being formed. the reversible reaction occurs at the same rate. the limiting reactant prevents the forward reaction occurring.