If the molar mass of a substance is found to be 638 grams/mole, what is the molecular formula?

Which best describes why nh4+ can form an ionic bond with ci-?

No copying 15 pts how does a free-body diagram tell you about the net force on an object?

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.