In addition to some propane and ethane, LPG cylinders contain mainly two isomers of another alkane. Name the two isomers and write their condensed structural formulae.

4 Name the scientist who disproved the ‘vital force theory’ for the formation of organic compounds. 5 Name the element whose allotropic form is graphite. 7 Buckminsterfullerence is a spherical molecule in which 60 carbon atoms are arranged in interlocking hexagonal and pentagonal rings of carbon atoms.

(a) How many hexagons of carbon atoms are present in one molecule of buckministerfullerene?

(b) How many pentagons of carbon atoms are present in one molecule of buckministerfullerence ?

8 Name the black substance of pencil. Will the current flow through the electrical circuit when we use the sharpened ends of the pencil to complete the circuit?