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Questions 6.2.1

  1. With what colour of flame does carbon burn in pure oxygen? Check the position of carbon in the Periodic Table.

  2. To which Group of the Periodic Table does carbon belong?

  3. Why is carbon expected to be reactive?

  4. What is the normal valency of carbon?

  5. Oxygen is in Group VI. Write the formula of expected product when carbon burns in oxygen. How can we test the product?

  6. Write the chemical equation for the burning of carbon in oxygen.


     Charcoal burnt in domestic charcoal burner

    Figure 6.2.1 Charcoal burnt in domestic charcoal burner


    Caution: Cutting down of trees and burning charcoal cause serious threats to the environment and climate. We should plant trees and use solar energy, biogas or electricity if available. Although burning methane also produdces carbon (IV) oxide, it saves trees from use as firewood.

  7. Figure 6.2.1 shows the effect of burning charcoal, an amorphous carbon, in a domestic charcoal burner. What is the evidence (reason for believing) that charcoal is not pure carbon?

  8. Are the impurities likely to be compounds of metals or non-metals? Explain (Hint: structure and physical state).




Answers to Questions 6.2.1

  1. A bright white flame
  2. Group IV
  3. It has incomplete energy level, with only four electrons instead of eight.
  4. Four (4)
  5. CO2
  6. C(s)   +   O2(g)   ⟶   CO2(g)
  7. The fact that ash is left as a solid residue; but carbon (IV) oxide is a gas.
  8. Compounds of metals. Oxides of non-metals have molecular structures; so they occur as liquids or escape as, leaving no solid residue.