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Stearic acid, CH₃(CH₂)₁₈COOH, is a common saturated fatty acid - VCE - SSCE Chemistry - Question 1 - 2003 - Paper 1
Question 1
Stearic acid, CH₃(CH₂)₁₈COOH, is a common saturated fatty acid. a. What is meant by the term ‘saturated’? b. Stearic acid can be used as a source of energy. Writ... show full transcript
Worked Solution & Example Answer:Stearic acid, CH₃(CH₂)₁₈COOH, is a common saturated fatty acid - VCE - SSCE Chemistry - Question 1 - 2003 - Paper 1
Step 1
What is meant by the term ‘saturated’?
Answer
The term 'saturated' refers to fatty acids that contain no double bonds between carbon atoms in their hydrocarbon chain. In saturated fatty acids, all carbon atoms are fully 'saturated' with hydrogen atoms, resulting in a straight-chain structure that allows them to pack closely together. This property generally leads to solid fats at room temperature.
Step 2
Write a chemical equation for the complete reaction between oxygen and stearic acid.
Answer
The complete combustion of stearic acid in the presence of oxygen can be represented by the following chemical equation:
In this reaction, stearic acid reacts with oxygen to produce carbon dioxide and water.
Step 3
Step 4
How does the additive prevent oils becoming rancid?
Answer
Antioxidants prevent oils from becoming rancid by reacting preferentially with oxygen. They inhibit the oxidation process, which is responsible for the spoilage of fats and oils, thereby extending the shelf life and maintaining the quality of the products.