Testing For Anions & Cations

1. Testing For Anions & Cations http://www.google.com.au/imgres?q=cation+comic&hl=en&biw=1093&bih=538&tbm=isch&tbnid=dizwhswY7cumeM:&imgrefurl=http://www.rosschurchley.com/category/blog/comics/&docid=hHXbptgEtjAw5M&imgurl=http://rchurchley.files.wordpress.com/2010/11/115-cheshire-cation.png&w=585&h=640&ei=BCouT9HsDI_omAWxlc3cDw&zoom=1&iact=hc&vpx=96&vpy=133&dur=3207&hovh=235&hovw=215&tx=87&ty=114&sig=109607668085463456387&page=1&tbnh=143&tbnw=131&start=0&ndsp=10&ved=1t:429,r:0,s:0

2. Today’s Lesson • Identification of Ions, Cations & Gases • Experiment • Practice Test

3. Testing Gases • Oxygen is flammable, so can be tested glowing splint. • Hydrogen is flammable, so can be tested with a lighted splint • Carbon Dioxide can be tested in Lime water and will form a precipitate of Calcium Carbonate • Ammonia gas will turn wet blue litmus paper red (alkali)

4. Testing for Halide Ions • You can test for Halides in acidic conditions (normally Nitric Acid or Hydrochloric Acid) • They will form a precipitate with Silver Nitrate. • Chloride ions forms a white precipitate (need to know this one) • Bromide ions form a cream precipitate • Iodide ions for a yellow precipitate

5. Testing Sulfate Ions • You test for Sulfate ions in acidic conditions (normally Hydrochloric acid) • Barium Sulfate is insoluble, so you adding Barium in acidic conditions will form Barium Sulfate if there is Sulfate present.

6. Testing Metal Ions • Many metal ions will form precipitates under basic or alkali conditions. This normally means they are in Sodium Hydroxide. • Copper 2+ makes a pale blue precipitate (Copper (II) Hydroxide) • Iron 2+ makes a green precipitate (Iron (II) Hydroxide) • Iron 3+ makes a red-brown precipitate (Iron (III) Hydroxide)

7. Carbonates • Adding Carbon Dioxide into lime water will turn it milky by making Calcium Carbonate • Adding an acid to this will reverse the reaction

8. Ammonia Ions • Ammonia (NH4+) can be testing in Sodium Hydroxide which is lightly heated. • If it is present, Ammonium will turn into Ammonia and water. It will make a smelly gas (Ammonia) and turn red litmus blue

9. Nitrate Ions • Sodium Hydroxide and Aluminium can be used to find Nitrate Ions. • Take a small amount of the solution with Al and Sodium Hydroxide. • Nitrate will form Ammonia and AlO2-

10. 1st Activity • Put some lime water into a test tube and then blow some air into the lime water with a straw. • What happens to the liquid? • Name the compound made. • Now put some dilute Hydrochloric acid into the test tube 3. Explain what has how happened?

11. 2nd Activity • In a test tube, put some Silver Nitrate and dilute Hydrochloric Acid together. • Explain what happens • If a reaction occurred, write down the reaction. • Was this under acidic or basic conditions?

12. 3rd Activity • Put a small amount of Calcium Carbonate into both lime water and hydrochloric acid. • Explain what happened for both samples. • Write down a balanced chemical reaction for each to show what happened

13. 4th Activity • Collect 4 test tubes and put a small amount of some Copper (II), Iron (II), Iron (III) and Ammonium into one test tube each • Now add the same amount of Sodium Hydroxide (NaOH) • Write down what happened • Now put in roughly the same amount of Hydrochloric Acid • Now describe what happened

14. 5th Activity • Add some Barium Chloride into a small amount of Sulfuric Acid into a test tube • Write down what happens • Write down the reaction that occurs.

15. 6th Activity • Put a small amount of Aluminum into HNO3in a test tube. • Also complete with NaOH and Aluminium • Explain what happens. • How could we find out whatthereaction is?