Carbon Dioxide (Oxford AQA IGCSE Chemistry): Revision Note

Exam code: 9202

Alexandra Brennan

Written by: Alexandra Brennan

Reviewed by: Stewart Hird

Updated on

Carbon Dioxide Test

  • The test for carbon dioxide involves bubbling the gas through an aqueous solution of limewater (calcium hydroxide)

  • If the gas is carbon dioxide, the limewater turns cloudy white

Testing for carbon dioxide gas

The diagram shows carbon dioxide bubbling through limewater, which turns cloudy / milky to confirm the presence of carbon dioxide
Limewater turns cloudy white in the presence of carbon dioxide

Examiner Tips and Tricks

Sometimes students think that extinguishing a burning splint indicates carbon dioxide gas. However, while it is a property of carbon dioxide, other gases, such as nitrogen, will also do this, so the test is not definitive and should not be quoted in an exam answer.

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Alexandra Brennan

Author: Alexandra Brennan

Expertise: Chemistry Content Creator / Senior Marketing Executive

Alex studied Biochemistry at Newcastle University before embarking upon a career in teaching. With nearly 10 years of teaching experience, Alex has had several roles including Chemistry/Science Teacher, Head of Science and Examiner for AQA and Edexcel. Alex’s passion for creating engaging content that enables students to succeed in exams drove her to pursue a career outside of the classroom at SME.

Stewart Hird

Reviewer: Stewart Hird

Expertise: Chemistry Content Creator

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.