(g) Give the reason why noble gases are chemically inert.
(a) An electrochemical cell is a device that can generate electrical energy from the chemical reactions occurring in it, or use the electrical energy supplied to it to facilitate chemical reactions in it.
(b)
| Electrochemical cell |
Electrolytic cell |
| Chemical reaction produces electric current |
Electricity is used to produce chemical reaction |
| The positive electrode is cathode |
Cathode is the negative electrode |
| Anode is the negative electrode |
Anode is the positive electrode |
| It does not require any external source of energy. |
It does require an external source of energy, thus it is non-spontaneous |
| Electrodes are in separate compartments |
Electrodes are in the same compartment |
(c) When powdered zinc is added to a copper (II) tetraoxosulphate (IV) solution, a reddish-brown solid of copper metal will form on the zinc, and the blue solution will become colourless as zinc displaces copper.
d(i) The reaction can be represented by the following equation: Zn(s) + CuSO\(_4\)(aq) → ZnSO\(_4\)(aq) + Cu(s).
(ii) Oxidation-Reduction (Redox) reaction
(e) Ammonia, Chlorine, Hydrogen Sulphide
(f) Factors that favor cracking include: high temperatures, high pressures, the presence of catalysts, and the nature of the material's composition and structure.
(g) Noble gases are chemically inert because their outermost electron shells are completely filled, making them stable and unlikely to react with other elements.
(h) Properties of homologous series include the following:
- All members of a homologous series have the same general formula.
- All members of a homologous series have the same functional group. e.g Alcohols contain the (-OH) functional group.
- The molecular formula of successive members of a homologous series differs by CH\(_2\).
- Members of a homologous series have similar physical properties, such as melting point, boiling point, and density.
- Members of a homologous series have similar chemical properties because they have the same functional group.
(i) Global warming is the increase in Earth's average temperature caused by greenhouse gases. Greenhouse gases trap heat in the atmosphere, which warms the planet. Carbon dioxide, methane, and nitrous oxide are greenhouse gases that trap heat in the atmosphere.
(j) Global warming is primarily caused by
- burning of fossil fuels
- increased concentration of greenhouse gases, like carbon dioxide (CO\(_2\))
