Question

Draw the condensed structural formula of each of the following compounds: a. 1,1 -dibromo-2-pentyne b. \(c i s-2\) -heptene

Short answer

1. Br2CH-C≡C-CH2CH3; 2. CH3-CH=CH-CH2-CH2-CH2-CH3.

Step-by-step solution

Understand the structure and formula

First, recognize the naming conventions of the compounds. '1,1-dibromo-2-pentyne' indicates a pentane chain (5 carbon atoms) with bromine atoms at the first carbon and a triple bond (yne) at the second carbon. 'cis-2-heptene' indicates a heptane chain (7 carbon atoms) with a double bond (ene) at the second carbon in the cis configuration.

Draw the carbon backbone for 1,1-dibromo-2-pentyne

Draw a 5-carbon chain for 1,1-dibromo-2-pentyne. The carbon chain is represented as follows: C-C≡C-C-C.

Add bromine atoms to 1,1-dibromo-2-pentyne

Place the bromine atoms on the first carbon atom. This is represented as: Br-C(Br)-C≡C-C-C.

Draw the carbon backbone for cis-2-heptene

Draw a 7-carbon chain for cis-2-heptene. The carbon chain is represented as follows: C-C=C-C-C-C-C.

Adjust for the cis configuration in cis-2-heptene

Since the double bond at the second carbon is in the cis configuration, the larger groups attached to the double-bonded carbons will be on the same side. This can be represented as: CH3-CH=CH-CH2-CH2-CH2-CH3.

Write the condensed structural formulas

Combine the information to write the condensed structural formulas. For 1,1-dibromo-2-pentyne, it is: Br2CH-C≡C-CH2CH3. For cis-2-heptene, it is: CH3-CH=CH-CH2-CH2-CH2-CH3.

Key concepts

1,1-dibromo-2-pentyne

1,1-Dibromo-2-pentyne is an interesting compound in organic chemistry. It contains a five-carbon chain (pentane) and distinctive groups which impart unique properties. The name reveals a lot about its structure:

The '1,1-dibromo' part indicates that two bromine atoms are attached to the first carbon atom in the chain.
The '2-pentyne' part tells us that there is a triple bond between the second and third carbon atoms.

To draw it, we start by sketching the carbon backbone: C-C≡C-C-C. The triple bond is represented as three lines connecting two carbon atoms. Next, we place the bromine atoms on the first carbon: Br-C(Br)-C≡C-C-C.

When we write its condensed structural formula, it looks like Br2CH-C≡C-CH2CH3. This breakdown helps to understand its molecular structure and the placement of atoms.

cis-2-heptene

Cis-2-heptene is another fascinating compound in organic chemistry. Its naming guides us to decipher its structure:

'Heptene' signifies a seven-carbon chain with a double bond (indicated by 'ene').
'2-' tells us that the double bond is between the second and third carbon atoms.
'Cis' means that the larger groups attached to the double-bonded carbons are on the same side of the bond.

First, draw the carbon backbone: C-C=C-C-C-C-C. In the 'cis' configuration, make sure both alkyl groups on the double-bonded carbons point in the same direction. The condensed structural formula thus becomes CH3-CH=CH-CH2-CH2-CH2-CH3. Notice how the double bond influences the shape of the molecule by causing a kink in the chain.

organic chemistry

Organic chemistry is the branch of chemistry dealing with carbon-containing compounds. It's crucial because most biomolecules, pharmaceuticals, and many industrial chemicals are organic. Here are some core concepts:

• Carbon's versatility: Carbon atoms can form stable bonds with many elements, including other carbon atoms. This ability results in a vast number of possible structures, like chains, rings, and branched structures.
• Functional groups: Specific groups of atoms within molecules have characteristic properties and reactivity. Examples include hydroxyl groups (-OH), carboxyl groups (-COOH), and halogens (like bromine in 1,1-dibromo-2-pentyne).
• Isomerism: Compounds with the same molecular formula can have different structures and properties. Cis-trans isomerism (like in cis-2-heptene) is one form of this phenomenon.

Knowing these basics helps to understand more complex organic molecules and reactions. Remember, organic chemistry builds up from simple molecules to very complex ones, so grasping these initial concepts is key.