GCSE Chemistry Question Analysis Topic: Chemistry - Short Questions
1) Describe the role of the following:
(i) SiO2 in the extraction of copper from copper matte.
(ii) NaCN in froth floatation process.
2) Which of the following is a fibre?
Nylon, Neoprene, PVC
3) Write the principle behind the froth floatation process. What is the role of collectors in this process?
1) (i) When copper is extracted from copper matte, SiO2 reacts with iron oxide to form ferrous silicate slag, which is then taken out.
Formula: FeO + SiO2 → FeSiO3
(ii) NaCN is utilised as a depressant in the froth flotation process to separate PbS and ZnS from ores. It removes PbS along with the froth while selectively preventing ZnS from reaching it.
2) Among the choices, nylon is the fiber. Terylene is one more kind of fibre. PVC and neoprene do not form fibre.
Strong hydrogen bonds allow the polymer chains to form fibres. These polymers have a high tensile strength.
3) The gangue particles of ore are preferentially wetted by water whereas the metallic sulphide particles are ideally wetted by oil in the froth flotation process.
Polar groups allow collectors to attach themselves to mineral grains, which later turn water-repellent and disperse into the froth. Ethyl xanthate and potassium ethyl xanthate are two examples.
End of analysis. Great!