Draw an 18-carbon unsaturated fatty acid that contains two carbon–carbon double bonds, one on carbon 6 and one on carbon 9 (count starting with the carboxyl carbon). Is this a “straight-chain” molecule or a “bent” molecule?

검증된 단계별 안내

Step 1: Begin by understanding the structure of a fatty acid. A fatty acid consists of a carboxyl group (-COOH) at one end and a long hydrocarbon chain. In this case, the chain contains 18 carbons.

Step 2: Identify the positions of the double bonds. The problem specifies that there are two carbon–carbon double bonds: one at carbon 6 and one at carbon 9. Number the carbon atoms starting from the carboxyl carbon (carbon 1).

Step 3: Draw the hydrocarbon chain with single bonds between carbons initially. Then, introduce the double bonds at the specified positions: between carbon 6 and carbon 7, and between carbon 9 and carbon 10. Ensure the rest of the carbons are connected by single bonds.

Step 4: Determine the geometry around the double bonds. Carbon–carbon double bonds in fatty acids typically have a cis configuration, which causes a bend in the molecule at each double bond. Draw the chain with bends at the positions of the double bonds to reflect this geometry.

Step 5: Conclude whether the molecule is 'straight-chain' or 'bent.' Since the cis double bonds introduce bends in the structure, this molecule is not a straight-chain molecule but a bent one.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

도움이 되었나요?

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Fatty Acid Structure

Fatty acids are carboxylic acids with long hydrocarbon chains. The structure includes a carboxyl group (-COOH) at one end, followed by a chain of carbon atoms. In unsaturated fatty acids, one or more double bonds exist between carbon atoms, affecting the molecule's shape and properties.

Unsaturation and Double Bonds

Unsaturation refers to the presence of double bonds in a fatty acid chain. Each double bond introduces a kink in the chain, preventing tight packing of the molecules. In this case, the presence of two double bonds at specific positions (carbon 6 and carbon 9) indicates that the fatty acid is unsaturated and will have a bent shape.

Molecular Geometry

Molecular geometry describes the three-dimensional arrangement of atoms in a molecule. In the case of fatty acids, the presence of double bonds leads to a bent or kinked structure, as opposed to a straight-chain configuration. This geometric difference influences the physical properties of the fatty acid, such as melting point and fluidity.