Chemistry - 4CH1 PearsonEdexcel

Alcohols

Overview

Alcohols are among the most versatile organic compounds. Ethanol alone serves as a fuel, a solvent, a drink ingredient, and a feedstock for making other chemicals. What gives this family its identity is a single functional group - the hydroxyl group, -OH - attached to a carbon chain.

In this lesson you will learn how to name and draw the first four alcohols, explore the three ways ethanol can be oxidised, and compare the two industrial routes for manufacturing ethanol: hydration of ethene and fermentation of glucose. These are high-yield specification points that Edexcel tests regularly.

Objectives

know that alcohols contain the functional group −OH
understand how to draw structural and displayed formulae for methanol, ethanol, propanol (propan-1-ol only) and butanol (butan-1-ol only), and name each compound the names propanol and butanol are acceptable
know that ethanol can be oxidised by: - burning in air or oxygen (complete combustion) - reaction with oxygen in the air to form ethanoic acid (microbial oxidation) - heating with potassium dichromate(VI) in dilute sulfuric acid to form ethanoic acid
know that ethanol can be manufactured by: - reacting ethene with steam in the presence of a phosphoric acid catalyst at a temperature of about 300 ºC and a pressure of about 60-70 atm - the fermentation of glucose, in the absence of air, at an optimum temperature of about 30 ºC and using the enzymes in yeast
understand the reasons for fermentation, in the absence of air, and at an optimum temperature

Lesson Note

When most people hear the word 'alcohol' they think of drinks. But to a chemist, alcohol is a whole family of molecules united by the -OH group. Methanol powers racing cars, ethanol is the world's most widely used biofuel, propanol dissolves nail varnish, and butanol is a promising next-generation fuel. Understanding their chemistry opens doors across the specification.

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Lesson Evaluation

Congratulations on completing the lesson on Alcohols. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

What is the functional group in alcohols? A) -COOH B) -OH C) C=C D) -CHO Answer: B
What colour change is observed when ethanol is heated with acidified potassium dichromate? A) Green to orange B) Orange to green C) Blue to colourless D) Purple to colourless Answer: B
Fermentation of glucose requires: A) Excess oxygen and high temperature B) Yeast, absence of air, and about 30 degrees Celsius C) A phosphoric acid catalyst D) High pressure and a platinum catalyst Answer: B
What is the structural formula of ethanol? A) CH3OH B) CH3CH2OH C) CH3CH2CH2OH D) CH3COOH Answer: B
Which of these is NOT a use of alcohols? A) Fuel B) Solvent C) Road surfacing D) Making vinegar Answer: C