Structural formulas of common organic compounds with their IUPAC names.

The image you've uploaded contains a grid of organic molecules, each with their structural formulas and simplified line-angle or condensed formulas. The task appears to be naming each compound based on its structure.

Let’s go through each molecule systematically, identify the functional group, and provide the IUPAC name (or common name where appropriate). We’ll also explain how we determine the name for each.

---

🔹 Row 1

1. CH₃CO₂H
- Structure: Carboxylic acid with two carbons
- Name: Acetic acid (common) / Ethanoic acid (IUPAC)

2. CH₃CHO
- Aldehyde with two carbons
- Name: Acetaldehyde (common) / Ethanal (IUPAC)

3. CH₃COCH₃
- Ketone with three carbons
- Name: Acetone (common) / Propanone (IUPAC)

4. CH₃COOCH₃
- Ester from acetic acid and methanol
- Name: Methyl acetate / Methyl ethanoate

5. CH₃CH₂OH
- Alcohol with two carbons
- Name: Ethanol

---

🔹 Row 2

6. CH₃CH₂CH₃
- Alkane with three carbons
- Name: Propane

7. CH₃CH=CH₂
- Alkene with three carbons, double bond at C1
- Name: Propene

8. HC≡CH
- Alkyne with two carbons
- Name: Ethyne

9. CH₃CONH₂
- Amide from acetic acid
- Name: Acetamide / Ethanimide

10. CH₃CH₂NH₂
- Primary amine with two carbons
- Name: Ethylamine / Ethanamine

---

🔹 Row 3

11. CH₃CH₂CH₂CH₃
- Alkane with four carbons
- Name: Butane

12. CH₃CH=CHCH₃
- Alkene with four carbons, double bond between C2–C3
- Name: But-2-ene

13. CH₃C≡CCH₃
- Alkyne with four carbons, triple bond in middle
- Name: But-2-yne

14. CH₃CONHCH₃
- N-methylacetamide
- Name: N-Methylacetamide / N-Methylethanamide

15. CH₃CH₂NHCH₃
- Secondary amine: ethyl + methyl
- Name: N-Methylethylamine / N-Methylpropan-1-amine? Wait — actually:

- Correct: Ethylmethylamine / N-Methylethanamine

But IUPAC: N-Methylethanamine is correct.

---

🔹 Row 4

16. CH₃CH₂CO₂H
- Carboxylic acid with three carbons
- Name: Propanoic acid

17. CH₃CH₂CHO
- Aldehyde with three carbons
- Name: Propanal

18. CH₃CH₂COCH₂CH₃
- Ketone with five carbons; carbonyl at C3
- Name: Pentan-3-one

19. CH₃COOCH₂CH₃
- Ester: acetic acid + ethanol
- Name: Ethyl acetate / Ethyl ethanoate

20. CH₃OH
- One-carbon alcohol
- Name: Methanol

---

✔ Final Answer Grid (Names to Fill in Boxes):

Here are the names to write in the blank boxes below each structure:

```
Row 1:
1. Ethanoic acid
2. Ethanal
3. Propanone
4. Methyl ethanoate
5. Ethanol

Row 2:
6. Propane
7. Propene
8. Ethyne
9. Ethanamide
10. Ethanamine

Row 3:
11. Butane
12. But-2-ene
13. But-2-yne
14. N-Methylethanamide
15. N-Methylethanamine

Row 4:
16. Propanoic acid
17. Propanal
18. Pentan-3-one
19. Ethyl ethanoate
20. Methanol
```

---

🔍 Explanation of Naming Rules Used:

- Carboxylic acids: suffix "-oic acid", e.g., CH₃COOH → ethanoic acid.
- Aldehydes: suffix "-al", e.g., CH₃CHO → ethanal.
- Ketones: suffix "-one", e.g., CH₃COCH₃ → propanone.
- Esters: named as alkyl alkanoate, e.g., CH₃COOCH₃ → methyl ethanoate.
- Alkanes: suffix "-ane", e.g., CH₃CH₂CH₃ → propane.
- Alkenes: suffix "-ene", double bond position indicated, e.g., CH₃CH=CH₂ → propene.
- Alkynes: suffix "-yne", e.g., HC≡CH → ethyne.
- Amides: suffix "-amide", N-substituents named with "N-", e.g., CH₃CONHCH₃ → N-methylethanamide.
- Amines: suffix "-amine", e.g., CH₃CH₂NH₂ → ethanamine.

---

Let me know if you'd like this formatted into a table or need help drawing structures!