Question

9- Which pair of formulae represents two alkanes? (1 mark)

A)CH4 and C8H18
B)C₂H6 and C5H8
C) C3H6 and C5H12
D) C₁0H8 and C4H8​

Answer 1

A) CH4 and C8H18

Step-by-step explanation:

• General Formula for an Alkane = CnH2n+2

• This means for every number of Carbon (C) atoms, there are twice as many Hydrogen (H) atoms with an additional two added onto that.

• Therefore, if there is one Carbon Atom, and we multiply that by two, and then add an additional two, we get 4 Hydrogen atoms, so CH4, which is our first Formulae

• Secondly, if we have eight Carbon Atoms, and we multiple that by two (16), and then add an additional two, we get 18 Hydrogen atoms, so C8H18, which is our second Formulae

• The other Formulas do not follow this 'General Formula'