General Principles & Processes of Isolation of Elements
- Give reasons for the following: 3
- Cryolite is added to alumina before its reduction.
- Reduction of a metal oxide is easier if the metal formed is in liquid state at the temperature of reduction.
- Copper can be extracted by hydrometallurgy but not zinc.
- Explain the cyanide process for isolation of silver. 2
- Differentiate between calcination and roasting. 2
- Outline the principles of the following processes : 3
- Froth floatation process
- Zone refining method.
- Explain the process for refining of nickel metal. 2
- Explain the role of : 2
- SiO2 in the metallurgy of Cu.
- Depressant in froth floatation process.
- Name the ores of following metals from which extraction taken place – Aluminium and Zinc. 1
- Consider the following reaction at 10000C 2
2 Zn(s) + ½ O2 (g) → ZnO (s) ΔG ̊ = – 360 KJmol-1
C (s) + ½ O2 (g) → Co(g) ΔG ̊ = – 460 KJmol-1
Predict whether C can be used as reducing agent for ZnO?
- Name of the following: 3
- Two metals which never exist in native state.
- Two metals which can exist in native as well as combined state.
- Two metals which always occur in native state.