Structural isomerism in the alkanes
2 marks · HardExplain why two different molecules with the formula C6H14 are considered structural isomers.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
They have the same molecular formula (C6H14) but different structural formulae (the atoms are connected in a different order).
Also accept: Same number and type of atoms but joined in different ways.; Have the same molecular formula but the structure (connectivity) of atoms is different.
Common mistakes: Saying only that they have different shapes, or only that they are different molecules without specifying difference in structure.; Confusing isomers with isotopes.
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States that the molecules have the same molecular formula.
B2 · 1 mark · States that they have different structural formulae or atoms are joined in different order.
Worked solution
Molecules with the formula C6H14 are considered structural isomers if they have:
• the same molecular formula (C6H14)
• different structural formulae (the atoms are joined in different ways)