Quiz & Worksheet - Organic Chemistry Naming | Study.com - Free Printable

Let's go through each question in the worksheet and solve them step by step.

---

Question 1: Name the image

Structure:
```
H H
| |
H - C = C - H
| |
H H
```

This is a three-carbon chain with a double bond between the first and second carbon atoms. The molecule has the formula C₃H₆.

- The longest carbon chain has 3 carbons → "prop" (from propane).
- There is a double bond → suffix changes to "-ene".
- The double bond starts at carbon 1 → "1-propene".

✔ Correct answer: 1-propene

> ✘ Incorrect options:
> - propane: That’s for saturated alkane (C₃H₈), no double bond.
> - 1,2-dipropene: Not a valid name; doesn’t make sense.
> - 1-propane: Invalid name; propane doesn't have a number like that.

---

Question 2: Name the image

Structure:
```
CH₃
|
CH₃–CH–CH–CH₃
|
CH₃
```

We need to identify the longest carbon chain and any substituents.

- Longest chain: 4 carbons → "butane"
- Two methyl groups (CH₃) are attached to carbons 2 and 3.
- So, we have 2,3-dimethylbutane

Let’s verify:
- Number the chain so that substituents get lowest numbers.
- If we number left to right: carbon 2 and 3 both have methyls → 2,3-dimethylbutane.
- If we number right to left: same thing → still 2,3-dimethylbutane.

✔ Correct answer: 2,3-dimethylbutane

> ✘ Other options:
> - "2-methyls and a butane": Poorly worded and incorrect naming.
> - "butene, dimethane": No double bond here; not an alkene.
> - "butane, 2,3-dimethyl": Correct structure but wrong format — IUPAC names use prefix + parent chain.

So best choice is: ✔ 2,3-dimethylbutane

---

Question 3: Which of the following is a main difference between alkanes and alkenes?

Let’s evaluate each option:

- Alkanes have a double bond between carbon atoms.
✘ False. Alkanes have only single bonds.

- Alkenes do not have a double bond.
✘ False. Alkenes do have at least one double bond.

- Alkenes have a double bond between carbon atoms.
✔ True. This is a defining feature of alkenes.

- Alkenes do not have side groups.
✘ False. Alkenes can have side groups (substituents). For example, 3-methyl-1-butene.

✔ Correct answer: Alkenes have a double bond between carbon atoms.

---

✔ Final Answers:

1. 1-propene
2. 2,3-dimethylbutane
3. Alkenes have a double bond between carbon atoms.

Let me know if you'd like diagrams or further explanation!