Video Transcript
For what separation process would the labware shown in the diagram below be used for?
We are asked about a separation process, which tells us that the labware is used in conjunction with a mixture and that the labware is used to divide the mixture into its different constituents. The diagram shows a liquid mixture in a round-bottom flask X. The mixture is being heated. The apparatus also has an adapter to which is fitted a thermometer. The adapter is joined to apparatus Y, which we can identify as a condenser by virtue of its structure, which consists of an outer glass tube called a jacket through which water is allowed to pass and an inner glass tube. Lastly, we see another form of adapter, which tapers and can deliver liquids to a variety of test tubes.
The separation process that uses this apparatus setup is distillation, a method for separating mixtures using the different volatilities of the components. First, the mixture is heated. The more volatile components are converted from a liquid to gas and are thus driven off. These vapors move into the adapter, pass the thermometer, which we can use to identify the vapors that are being driven off at that point in time by virtue of their boiling point. The vapors then move down into the inner tube of the condenser. Here, they are cooled and condensed into liquid as a result of the coolant water constantly moving through the outer jacket of the condenser. This purified liquid is collected in a test tube. We call this liquid a fraction, since it is only one component of the original liquid mixture.
Steps one to four are repeated over and over at different boiling points as the liquid mixture is progressively heated. When multiple fractions are collected, as shown by the multiple test tubes, we call the process fractional distillation. Fractional distillation is thus a sequential method of separating the components of a mixture, yielding multiple fractions.
Sometimes at step two, just above the round-bottom flask or distillation flask, an extra piece of equipment is added called a fractionating column. The fractionating column improves the purity of the vapors and thus helps in separating the different fractions from each other. The question asked “For what separation process would the labware shown in the diagram below be used for?” The answer is fractional distillation.
