Deep Dive: Understanding Alkanes

The General Formula: CₙH₂ₙ₊₂

• n = number of carbon atoms
• Plug in n to find the formula for any alkane
• Example: n=3 → C₃H₂₍₃₎₊₂ = C₃H₈ (propane)

Why "Saturated"?

• Alkanes have ONLY single bonds between carbons
• This means every carbon is bonded to as many hydrogens as possible
• The molecule is "saturated" with hydrogen — can't hold any more!
• Compare to alkenes which have C=C double bonds (unsaturated)

The First Four Alkanes (MUST memorise!):

Name	Formula	Carbons	State at room temp
Methane	CH₄	1	Gas
Ethane	C₂H₆	2	Gas
Propane	C₃H₈	3	Gas
Butane	C₄H₁₀	4	Gas

Naming Pattern: Meth (1), Eth (2), Prop (3), But (4), Pent (5), Hex (6)... + "ane"

Properties of Alkanes:

• Longer chains = higher boiling point (stronger forces between molecules)
• First four are gases, then liquids, then waxy solids
• Don't mix with water (immiscible)
• Burn well in oxygen (good fuels!)
• Generally unreactive — only combustion and reactions with halogens