Pure caffeine has a melting point of around 235 C. Suppose after you isolated your caffeine from coffee, you found that your sample had a melting point range of 230.3- 236.5 C. Would you conclude that your sample was pure or impure? it's pure because the range included the melting point of pure caffeine Oit's pure because the melting point range is narrow it's impure because the melting point range is broad it's probably wet