Tags: organic chemistry, chemical structures, alkanes, alkenes, molecular formulas, structural formulas, hydrocarbons, chemistry education, IUPAC naming, functional groups, carbon chains

It looks like you've uploaded a table with several organic molecules, and the task is likely to name each compound using IUPAC nomenclature. Since I can't view images directly, I’ll interpret the structures based on your description and solve each one step by step.

Let’s go through each structure (11–15) and name them correctly:

---

11.

Structure:
```
CH3
|
CH3–CH–CH2–CH3
|
CH3
```

This is a branched alkane. The longest carbon chain is 4 carbons (butane). There are two methyl groups attached to carbon 2.

- IUPAC Name: 2,2-dimethylbutane

> ✔ *Note: The longest chain is actually 4 carbons, but there's a methyl group on C2 and another methyl also on C2 → so it's 2,2-dimethylbutane.*

---

12.

Structure:
```
CH3
|
H3C–CH2–CH2–CH–CH2–CH2–CH3
```

Longest carbon chain: 7 carbons → heptane
There is a methyl group on carbon 4.

- IUPAC Name: 4-methylheptane

> ✔ *Numbering from left or right? Both ends give same result since symmetric in numbering — C4 is middle.*

---

13.

Structure:
```
CH3
|
H3C–CH2–CH2–CH2–CH–CH2–CH3
```

Longest chain: 7 carbons → heptane
Methyl group on carbon 4

- IUPAC Name: 4-methylheptane

> ✔ Same as #12 — both are 4-methylheptane.

Wait — let’s double-check the structure:

Actually, if it's:
```
H3C–CH2–CH2–CH2–CH(CH3)–CH2–CH3
```
Yes, that’s still 4-methylheptane

But wait — is this different from #12?

No — they are identical. Unless drawn differently, but both have a methyl on C4 of a 7-carbon chain.

So yes, 4-methylheptane

> ⚠️ But if the branching is different, maybe not. Let me assume it's correct.

---

14.

Structure:
```
H CH3H
\ /
H3C–C=C–C–CH3
/ \
H H
```

Let’s rewrite clearly:

The central bond is a double bond between two carbons.

Left side:
- Carbon bonded to: H3C–, H, H, and double bond → so it's CH3–CH=...

Right side:
- Carbon bonded to: CH3, H, H, and double bond → so =CH–CH3

But wait: the structure shows:

```
H3C–C(H)=C(H)–CH3
| |
CH3 CH3
```

Wait — no. Let’s look again.

Given:

```
H CH3H
\ /
H3C–C=C–C–CH3
/ \
H H
```

That seems messy. Probably meant to be:

Carbon 1: CH3–
Carbon 2: C with H and H → so CH3–CH=
Then double bond to carbon 3: which has H and CH3 → so =CH–CH3
And carbon 3 is also bonded to a carbon with CH3 and H and H → so it's –CH(CH3)–CH3?

Wait — better interpretation:

The molecule is:

```
H3C–CH=CH–CH(CH3)–CH3
```

But the drawing shows:

- Left: CH3–C(H)=
- Right: =C(H)–C(CH3)(H)–CH3

So:

- Carbon 1: CH3–
- Carbon 2: CH=
- Carbon 3: =CH–
- Carbon 4: CH(CH3)–
- Carbon 5: CH3

So full chain: CH3–CH=CH–CH(CH3)–CH3

Now find longest chain: 5 carbons → pentene
Double bond between C2 and C3
Substituent: methyl on C4

Now number to give double bond lowest number → start from left: double bond at C2 → good

So: 4-methylpent-2-ene

But wait — is that correct?

Chain: C1–C2=C3–C4–C5
C4 has a methyl group → so total 6 carbons

But we can have longer chain?

Wait: C1–C2=C3–C4–C5 and C4 has methyl → so C4 is tertiary carbon

But the longest chain is still 5 carbons. However, if we include the methyl on C4, can we make a 6-carbon chain?

Try: CH3–CH=CH–CH(CH3)–CH3

Can we renumber? If we go from right:
C1' = CH3 (from end), C2' = CH(CH3), C3' = CH, C4' = CH, C5' = CH3

But now double bond is between C3' and C4', so position 3 → higher than 2

So better to number from left → double bond at 2

So name: 4-methylpent-2-ene

But wait — is there a better way?

Wait — what if we consider the branch as part of chain?

No — because the methyl is on C4, so it's a side chain.

But check: is there a 6-carbon chain?

No — the branch is only one carbon.

So 4-methylpent-2-ene

But let’s confirm atoms:

- C1: CH3–
- C2: =CH–
- C3: =CH–
- C4: CH(CH3)–
- C5: CH3

Yes.

But wait — is the double bond between C2 and C3? Yes.

But in standard notation: pent-2-ene, methyl on C4 → 4-methylpent-2-ene

✔ Correct.

However, note: C4 is chiral? No need for stereochemistry unless specified.

But in this case, no stereoisomers indicated.

So final name: 4-methylpent-2-ene

---

15.

Structure:
```
H
|
H–C=C–CH2CH3
| |
H CH3
```

So:

- Left carbon: H–C–H → CH2
- Double bond to right carbon: C(CH3)–CH2CH3

So structure: CH2=CH(CH3)CH2CH3

Wait — no:

Actually:

- Left: H–C–H → carbon with two H’s → CH2
- Double bond to carbon that has: CH3 and CH2CH3

So: CH2=C(CH3)CH2CH3

Yes!

So: CH2=C(CH3)CH2CH3

This is a butene derivative.

Longest chain: 4 carbons, but double bond at end.

The carbon after double bond has two alkyl groups: methyl and ethyl.

So: 3-methylbut-1-ene? Wait — no.

Let’s number:

If we number from left:

- C1: CH2=
- C2: C(CH3)CH2CH3 → so C2 has methyl and ethyl

So: CH2=C(CH3)CH2CH3

So: 3-methylbut-1-ene? No — but-1-ene would be 4 carbons.

But here, C1 = CH2=
C2 = C(CH3)–
C3 = CH2–
C4 = CH3

So chain is: C1=C2–C3–C4 → 4 carbons

But C2 has an extra methyl → so total 5 carbons

So it's 3-methylbut-1-ene? Wait — no:

Wait: the chain is:

- C1: CH2=
- C2: C(CH3)–
- C3: CH2–
- C4: CH3

So the parent chain is but-1-ene, and a methyl group on C2?

But C2 is sp² carbon — so yes.

But wait — the carbon after double bond is C2, which has:

- Bond to C1 (double bond)
- Bond to CH3
- Bond to CH2CH3

So it's a tertiary carbon — but in alkenes, that’s fine.

So the chain is: CH2=C(CH3)CH2CH3

This is known as 3-methylbut-1-ene? Let’s see:

- But-1-ene: CH2=CH–CH2–CH3
- But here: CH2=C(CH3)CH2CH3 → so the second carbon has methyl and ethyl

So it's 3-methylbut-1-ene? No — that would be CH2=CH–CH(CH3)–CH3

We have: CH2=C(CH3)CH2CH3 → this is 3-methylbut-1-ene? No — that’s incorrect.

Wait — let’s count:

In CH2=C(CH3)CH2CH3, the longest chain is 4 carbons, but the substituent is on C2.

So the parent chain should be but-1-ene, and the methyl group is on C2.

But C2 is the first carbon of the chain? No — C1 is CH2=, C2 is C(CH3)CH2CH3

So C2 has a methyl group → so it's 2-methylbut-1-ene

Wait — but “but” implies 4 carbons in chain.

But in 2-methylbut-1-ene, the chain is:

- C1: CH2=
- C2: C(CH3)–
- C3: CH2–
- C4: CH3

Yes — that’s exactly CH2=C(CH3)CH2CH3

So the name is: 2-methylbut-1-ene

✔ Correct.

Alternatively, sometimes called isopentenyl, but IUPAC is 2-methylbut-1-ene

---

✔ Final Answers:

| Number | Structure | IUPAC Name |
|--------|-----------|------------|
| 11 | Branched alkane with two methyls on C2 of butane | 2,2-dimethylbutane |
| 12 | Methyl group on C4 of heptane | 4-methylheptane |
| 13 | Methyl group on C4 of heptane | 4-methylheptane |
| 14 | CH3–CH=CH–CH(CH3)–CH3 | 4-methylpent-2-ene |
| 15 | CH2=C(CH3)CH2CH3 | 2-methylbut-1-ene |

---

🔍 Summary:

- 11: 2,2-dimethylbutane
- 12: 4-methylheptane
- 13: 4-methylheptane
- 14: 4-methylpent-2-ene
- 15: 2-methylbut-1-ene

Let me know if you'd like the structures redrawn or explained further!