🌿 Naming Organic Compounds – Quick Guide
What are the main types?
- -ane ➜ Alkanes – saturated, single‑bonded carbon chains. Think of them as “single‑shelled houses” where every room (carbon) is connected by a single door (single bond).
- -ene ➜ Alkenes – one or more double bonds. Imagine a house with a double‑door that lets in extra guests (the double bond).
- -ol ➜ Alcohols – contain a hydroxyl group (-OH). Picture a house with a tiny garden (the OH group) that can host a party.
- -oic acid ➜ Carboxylic acids – contain a carboxyl group (-COOH). Think of a house with a big, friendly mailbox (COOH) that always sends letters (acidic protons).
Identifying the type from the name
- Look at the ending of the name.
- Match it to the table below.
- Confirm with the number of carbon atoms if needed.
| Ending | Compound Type | Example |
|---|
| -ane | Alkane | methane, ethane |
| -ene | Alkene | ethene, propene |
| -ol | Alcohol | ethanol, isopropanol |
| -oic acid | Carboxylic Acid | acetic acid, benzoic acid |
From a Molecular Formula
1️⃣ Alkanes: \$CnH{2n+2}\$
2️⃣ Alkenes: \$CnH{2n}\$
3️⃣ Alcohols: \$CnH{2n+1}OH\$
4️⃣ Carboxylic acids: \$CnH{2n}O_2\$
Example: C3H8 → \$C3H{2*3+2}\$ → Alkane (propane).
Example: C2H4O2 → matches \$CnH{2n}O_2\$ → Carboxylic acid (acetic acid).
From a Displayed Formula (Structural Formula)
- 🧪 Alkane example:
CH3-CH2-CH3 – all single bonds. - 🧪 Alkene example:
CH2=CH-CH3 – one double bond. - 🧪 Alcohol example:
CH3-CH2-OH – an -OH group attached to a carbon chain. - 🧪 Carboxylic acid example:
CH3-COOH – a carbonyl (C=O) next to an OH.
Quick Practice
- What type is butane? ➜ Alkane (ends in -ane).
- Identify the type of C4H8. ➜ Alkene (fits \$CnH{2n}\$).
- Which group is present in ethanol? ➜ -OH (alcohol).
- What is the functional group in acetic acid? ➜ -COOH (carboxylic acid).
Remember the “House” Analogy!
• Alkanes – single‑shelled houses (only single bonds).
• Alkenes – double‑door houses (one double bond).
• Alcohols – houses with a garden (OH group).
• Carboxylic acids – houses with a mailbox (COOH group).
Use these visual cues to quickly spot the type of compound when you see a name, formula, or structure. Happy naming! 🚀