The caffeine in a sample of tea is extracted by combining 80.0 ml of the tea with 15.0 ml of dichloromethane. If 89% of the caffeine is extracted after a single step, what is the distribution ratio of caffeine under these conditions?

A separation of alcohols by gas chromatography gives a peak for air (representing a non-retained substance) at 0.45 min at a flow rate of 10.0 ml/min. The retention time for 2-propanol is 3.01 min. What is the void volume of this chromatographic system? What was the total retention volume for 2-propanol on this system?