GCSEChemistryAQARevision NotesChemical AnalysisMethods of Identifying IonsCarbonates

Carbonates (AQA GCSE Chemistry): Revision Note

Exam code: 8462

Stewart Hird

Written by: Stewart Hird

Reviewed by: Caroline Carroll

Updated on

Test for carbonates

  • Carbonates all contain the carbonate ion, CO32-

  • The test for this ion involves adding dilute acid and testing the gas released

  • If a carbonate compound is present then effervescence should be seen and the gas produced is CO2 which forms a white precipitate of calcium carbonate when bubbled through limewater:

CO32- (aq) + 2H+ (aq) → CO2 (g) + H2O (l)

CO2 (g) + Ca(OH)2 (aq) → CaCO3(s) + H2O(l)

  • The white precipitate turns limewater cloudy 

Test for carbonates 

Test for carbonates by bubbling the gas produced when acid is added to a metal carbonate into limewater

Limewater turns cloudy in the presence of CO2 

Examiner Tips and Tricks

You’ll need to connect the test tube of the suspected ion to the test tube of limewater quickly so none of the CO2 escapes.

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

I would just like to say a massive thank you for putting together such a brilliant, easy to use website.I really think using this site helped me secure my top gradesin science and maths. You really did save my exams! Thank you.

Beth
IGCSE Student

This website is soooo useful and I can’t ever thank you enough for organising questions by topic like this. Furthermore, the name of the website could not have been more appropriate as it literally did SAVE MY EXAMS!

Fathima
A Level Student

Incredible! SO worth my money, the revision notes have everything I need to know and are so easy to understand. I actually enjoy revising! It makes me feel a lot more confident for my GCSEs in a few months.

Kate
GCSE Student

Absolutely brilliant, both my girls used it for A levels and GCSE. It's saves on paper copies, also beneficial exam questions ranked from easy to hard. It's removed a lot of stress from the exams.

Sameera
Parent

Just to say that your resources are the best I have seen and I have been teaching chemistry at different levels for about 40 years

Mark
Chemistry Teacher

Excellent

Our rating represented in Trustpilot stars
Read more reviews

Build on this topic

Check your understandingTry an Exam Question on this topicTest your recallReinforce key facts and definitions with FlashcardsLearn at your levelTake a Smart Lesson that adapts to your performance
Previous:Metal HydroxidesNext:Halides
Author
Reviewer
Stewart Hird

Author: 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.

Caroline Carroll

Reviewer: Caroline Carroll

Expertise: Head of Content Delivery

Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about delivering high-quality resources to help students achieve their full potential.