9. Cement is made by heating clay with crushed calcium carbonate. During this process, the calcium carbonate is first converted to calcium oxide.
(a) Suggest why calcium oxide is used to neutralise acidic soils.
2 . Sorrel is a small green plant.
(a) The pigments in the sorrel leaf can be separated by chromatography.
(i) Describe how chromatography can be used to separate different pigments.
(ii) Explain what is meant by Rf value.
(b) Sorrel plants contain a...