1. www.thescienceteacher.co.ukwww.thescienceteacher.co.uk | resources for science teachers who like to think TopicTests for ions and gasesLevelGCSE Outcomes1.To desrcibe the tests for common gases 2.To describe the tests for common cations and ions 3.To identify an unknown ionic compound from its ion tests

2. Name of gasFormulaDescription of test and positive result hydrogen oxygen carbon dioxide ammonia chlorine What am I? 1.I am diatomic, used in respiration and relight a glowing splint? 2.I am produced by respiration and turn lime water cloudy? 3.I bleach damp litmus paper and was used in the trenches? 4.I am a fuel that can be used in cars, I only produce water when I combust? 5.I am made of 4 atoms and turn damp red litmus paper blue?

3. IonFlame colour Li 1+ Na 1+ K 1+ Ca 2+ IonPrecipitate colour with NaOH Formula of precipitate Cu 2+ Fe 2+ Fe 3+ IonPrecipitate colour with AgNO 3 with HNO 3 Formula of precipitate Cl 1- Br 1- I 1- IonTestPositive result NH 4 + SO 4 2- CO 3 2- If you're not part of the solution, you're part of the precipitate!

4. NaCl e.g Na + Cl - KBr CuCO 3 CaI 2 Yellow flame white precipitate with AgNO 3 in HNO 3

5. FeI 3 FeSO 4 CaCO 3 LiI

6. Blue precipitate with NaOH Add HCl and bubbles form Lilac flame Cream precipitate with AgNO 3 Brick red flame White precipitate with BaCl 2 Red flame Yellow precipitate with AgNO 3