You know for the dot point which requires you to know about a person working in a particular branch of chemistry and what principle they use?
My example is:
John Smith is a production chemist at a plant which produces ammonia through the Haber process. The branch of chemistry that he undertakes is analytical chemistry which involves the analysis of the chemical contents of substances and mixtures. A chemical principle that John will employ is that of solubility as he uses gas-liquid chromatography to identify the substances present as the gas is passed over a liquid stationary phase. If the ratio of nitrogen to hydrogen is not roughly 1:3, efficiency may be reduced. In addition, if carbon monoxide or sulfur is present, the catalyst may be poisoned, resulting in the need for it to be replaced.