This common misconceptions covers Common Misconceptions within Alkanes for GCSE Chemistry. Topic 38: Alkanes It is section 8 of 12 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
⚠️ Common Misconceptions
Misconception 1: "Methane has double bonds"
Methane (CH₄) is the simplest alkane — it has only single bonds. One carbon bonded to four hydrogens: C has 4 bonds, each H has 1 bond. There is absolutely no C=C double bond in any alkane. The "saturation" in "saturated" means every possible hydrogen has been added — no room for more.
Misconception 2: "Saturated means the molecule has absorbed lots of energy"
In chemistry, "saturated" has a specific structural meaning — it refers to carbon compounds where all C-C bonds are single bonds. It has nothing to do with energy absorption. The molecule is "saturated" with hydrogen — every carbon has as many hydrogens as it can possibly bond to.
Misconception 3: "All alkanes are gases"
Only the first four alkanes (methane to butane, C1-C4) are gases at room temperature. C5-C17 are liquids (petrol, kerosene, diesel), and C18+ are waxy solids (like candle wax). The boiling point increases with chain length because of stronger forces between molecules.
Practice questions for Alkanes
What is the general formula for the alkane homologous series?
Explain why the boiling point of alkanes increases as the chain length increases.