now replace the red ball on each of the models with a second white ball. are the models mirror images of each other? does either possess a plane of symmetry? are the models superimposable? do the models represent identical or different structures? do the models represent enantiomers? why or why not? now switch any two balls on one of the models. does this change anything in terms of the answers to the questions above? objects that possess a plane of symmetry are never chiral. explain why.