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Unformatted text preview: rified unknown is mixed with benzoic acid (pure melting point 121122C) in one capillary and succinimide (pure melting point 122124C) is mixed with the unknown in another capillary. The benzoic acid/unknown mixture melts from 110 120C, and the succinimide/unknown mixture melts from 122123C. Can you determine the unknown from this data? Adding impurities to a compound will lower and broaden a melting point, therefore if you added an unknown to succinimide and the mp was the same the unknown must be succinimide. 5. (3 points) You have a mixture of 8 ml each of pentane (BP 36 oC), cyclohexane (BP 80 oC), and butanol (BP 118 oC), mixed together in a 50ml round bottom flask. Answer the following questions below: a. Which species would distill off last? butanol pentane b. Which species has the highest vapor pressure? c. What type of distillation would you perform? fractional distillation d. (2 points) During your steam distillation, what collected as the distillate? Briefly explain. The distillate is water + limonene. Since limonene is a natural product it is needs to be steam distilled, as straight distillation would cause the compound to decompose. During steam distillation, water is always part of the distillate. e. (2 points) How can the problem of bumping be minimized during a distillation? Briefly explain. Adding boiling chips (or a stir bar) will provide a nucleation site to release kinetic energy that builds up....
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- Spring '11