Chemistry - 0620 CIE

Oxides

Overview

Oxygen reacts with almost every element to form an oxide, but those oxides do not all behave the same way. Some turn water acidic, others make it alkaline, and a few can do either. Sorting oxides by how they react with acids and bases reveals a neat pattern that follows the periodic table.

In this lesson you will learn to classify oxides as acidic or basic and link this to whether the element is a metal or a non-metal. You will also meet amphoteric oxides, the in-between cases that react with both acids and bases, such as those of aluminium and zinc, and understand why they sit on that boundary.

Objectives

Classify oxides as acidic, including SO₂ and CO₂, or basic, including CuO and CaO, related to metallic and non-metallic character.
[Supplement] Describe amphoteric oxides as oxides that react with acids and with bases to produce a salt and water.
[Supplement] Classify Al O and ZnO as amphoteric oxides 2 3.

Lesson Note

Oxides are everywhere: in the air we breathe, the rust on iron, the lime spread on fields and the gases that cause acid rain. Knowing whether an oxide is acidic or basic tells you how it will react and what it can be used for, and it ties directly to where its element sits in the periodic table.

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Lesson Evaluation

Congratulations on completing the lesson on Oxides. 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.

Which oxide is acidic? A. CaO B. CuO C. CO2 D. Na2O Answer: C
Which oxide is basic? A. SO2 B. CuO C. CO2 D. NO2 Answer: B
Which oxide is amphoteric? A. CaO B. SO2 C. Al2O3 D. CO2 Answer: C
An amphoteric oxide reacts with: A. Acids only B. Bases only C. Both acids and bases D. Neither acids nor bases Answer: C
Acidic oxides are generally oxides of: A. Metals B. Non-metals C. Noble gases D. Transition elements Answer: B