1.1. Chromatography is a technique that can be used to separate a mixture into individual components on the basis of their solubility in a particular solvent. A small amount of the mixture to be separated is dropped onto a piece of chromatography paper at a position marked as the baseline, before the paper is suspended in a solvent.  The solvent travels up the paper and the components appear as dots on the paper at the point at which they come out of solution. 

Figure 1 shows the results obtained when a mixture of two amino acids is separated using chromatography. 

Figure 1

One way of identifying the components of a mixture is to calculate a value known as the R_f value. Use the equation provided below to calculate the R_f value of alanine in Figure 1. 

                               R_f = $\frac{Distancemovedbytheaminoacids}{Distancebetweenthebaselineandthesolventfront}$

1.2. Table 1 shows the properties of amino acids that determine their R_f values for a particular solvent and chromatography medium.

Table 1

Complete Table 1 to indicate the likely R_f values for amino acids with the properties described.

1.3. State how a scientist might use the results of a chromatography experiment to identify an unknown amino acid. 

1.4. Suggest one branch of science where chromatography techniques, like the one used to separate a mixture of amino acids, have a practical application.