FUNCTIONAL GROUPS (Organic Chemistry) worksheet - Free Printable

Let’s go step by step to solve this activity.

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Step 1: Understand the Task

You’re asked to group molecules based on their similarities in structure, especially focusing on:
- The functional group (a specific group of atoms that gives a molecule its characteristic chemical properties).
- The type of bonds and elements attached to the carbon chain.
- Don’t worry too much about how many carbon atoms there are — focus on the “special part” of the molecule.

We need to:
1. Identify each molecule’s functional group.
2. Group them together if they have the same functional group.
3. Write the letter(s) for each group.
4. Explain why they belong together.

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Step 2: Learn What Functional Groups Look Like

Here are common functional groups you’ll see here:

- Alcohol: –OH group attached to carbon → e.g., R–OH
- Ether: Oxygen between two carbons → R–O–R’
- Aldehyde: Carbonyl group (C=O) at the end of a chain, with H attached → R–CHO
- Ketone: Carbonyl group (C=O) in the middle of a chain → R–CO–R’
- Carboxylic Acid: –COOH group → R–COOH
- Ester: –COO– group, often written as R–COO–R’
- Amine: Nitrogen with hydrogens or alkyl groups → R–NH₂, R₂NH, R₃N
- Amide: Carbonyl + nitrogen → R–CONH₂

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Step 3: Go Through Each Molecule and Identify Its Functional Group

Let’s label each one:

A: CH₃–O–CH₃ → Ether
B: CH₃–CH₂–OH → Alcohol
C: CH₃–CH₂–CH₂–OH → Alcohol
D: H–CHO → Aldehyde
E: CH₃–O–CH₂–CH₃ → Ether
F: CH₃–CH₂–CH₂–CH₂–OH → Alcohol
G: CH₃–CH₂–O–CH₂–CH₃ → Ether
H: CH₃–CHO → Aldehyde
I: CH₃–CO–CH₂–CH₃ → Ketone
J: CH₃–CH₂–NH₂ → Amine
K: CH₃–CO–CH₃ → Ketone
L: H–CONH₂ → Amide
M: CH₃–COOH → Carboxylic Acid
N: CH₃–CH₂–COOH → Carboxylic Acid
O: CH₃–COO–CH₃ → Ester
P: CH₃–CH₂–COO–CH₂–CH₃ → Ester
Q: CH₃–COO–CH₂–CH₃ → Ester
R: CH₃–CONH–CH₃ → Amide
S: CH₃–NH₂ → Amine
T: H–COOH → Carboxylic Acid
U: CH₃–CH₂–CHO → Aldehyde

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Step 4: Group Them by Functional Group

Now let’s group them:

#### ➤ Alcohols (–OH):
B, C, F
→ All have –OH attached to a carbon chain.

#### ➤ Ethers (R–O–R’):
A, E, G
→ Oxygen sandwiched between two carbon groups.

#### ➤ Aldehydes (R–CHO):
D, H, U
→ Carbonyl (C=O) at the end, with H attached.

#### ➤ Ketones (R–CO–R’):
I, K
→ Carbonyl (C=O) in the middle of the chain.

#### ➤ Carboxylic Acids (R–COOH):
M, N, T
→ Have –COOH group.

#### ➤ Esters (R–COO–R’):
O, P, Q
→ Have –COO– linkage, usually with an alkyl group on both sides.

#### ➤ Amines (R–NH₂, etc.):
J, S
→ Have nitrogen with hydrogens or alkyl groups attached.

#### ➤ Amides (R–CONH₂, etc.):
L, R
→ Have carbonyl directly attached to nitrogen.

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Step 5: Final Answer Format

The task says:
> Organize these molecules in the table just by writing the letter that represent them. Do not forget to indicate the categories or classifications that made you decide why these molecules belong to the group.

So we’ll present it like this:

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Final Answer:

Alcohols (–OH group): B, C, F
Ethers (C–O–C): A, E, G
Aldehydes (–CHO): D, H, U
Ketones (–CO–): I, K
Carboxylic Acids (–COOH): M, N, T
Esters (–COO–): O, P, Q
Amines (–NH₂ or N with alkyl groups): J, S
Amides (–CONH₂ or similar): L, R

Each group shares the same functional group — the key part of the molecule that determines its chemical behavior. For example, all alcohols have an –OH group, which makes them able to form hydrogen bonds and react similarly.