C12 - chemical analysis - chromatography and rf values

Question 1

retention factor

Answer 1

The ratio between the distance travelled by the substance
and the distance travelled by the solvent.

Question 2

what are the phases of chromatography?

Answer 2

a stationary phase where particles can’t move (the filter
paper in most cases), a mobile phase where particles can move (a solvent for example
water).

Question 3

how to test if a substance is pure or impure

Answer 3

Different compounds will have different Rf values in different solvents, this allow us to see
whether a substance is pure or impure.

Question 4

formulations

Answer 4

Formulations are mixtures made using a precise amount
of each substance, so they can serve a particular purpose.

For example in paints or in pills.

Question 5

transition metals

Answer 5

• The central block (between group 2 and 3) of the Periodic Table is known as the
  transition metals.
• Compared to group 1 elements, transition metals have different physical properties.
  For example transition metals have a higher melting point and are more dense.
• The exception is mercury which is a liquid at room temperature.
• Transition metals also have different physical properties to group 1. They are much
  less reactive and do not react vigorously with oxygen or water.