Practical revision

• How to test for carbonate anions?


  Add dilute nitric acid, then test for carbon dioxide gas (bubble through limewater). Effervesence and carbon dioxide gas will be present if dilute nitric acid is added to carbonate anions.
• Test for chloride anions?


  Acidify with dilute nitric acid, then add aqueous silver nitrate - white ppt will form.
• Test for bromine anions?


  Acidify with dilute nitric acid, add aqeous silver nitrate - cream ppt will form
• Test for iodide anions?

  Acidify with dilute nitric acid, add aqeous silver nitrate - yellow ppt forms
• Test for nitrate anions?


  Add aqeous sodium hydroxide, then aluminium foil and warm carefully - ammonia will be produced (which can be tested as it turns damp red litmus blue).
• Test for sulfate anions?


  Acidify with dilute nitric acid, then add aqeous barium nitrate - white ppt forms
• Test for sulfite anions?


  Add a small volume of acidificed aqueous potassium manganate (VII) - will chnage from purple to colourless in presence of sulfite anions.
• Test for aluminium cation? (Al+)


  In sodium hydroxide - White ppt, soluble in excess with a colourless solution.

  In aqueous ammonia - white ppt, insoluble in excess
• Test for ammonium cation (NH4+)

  Aqueous sodium hydroxide - ammonia produced on warming (can be identified by turning damp red litmus blue).
• Tets for calcium cation (CA2+)


  Aqeuous sodium hydroxide = White ppt forms, insoluble in excess.

  Aqueous ammonia = no ppt, or a very slight white ppt.
• Test for chromium cation (Cr3+)


  Aqueous sodium hydroxide = green ppt forms, soluble in excess

  Aqueous ammonia = Green ppt, insoluble in excess
• Test for copper cation (Cu2+)

  Aqueous sodium hydroxide = Light blue ppt forms, insoluble in excess

  Aqueous ammonia = light blue ppt forms, soluble in excess giving a dark blue solution.
• Test for iron (II) cation (Fe2+)


  Aqueous sodium hydroxide = red-brown, insolble in excess ppt - turns brown near surface on standing

  Aqueous ammonia = Green ppt, insoluble in excess ppt - turns brown near surface on standing
• Test for iron (III) cation (Fe3+) 


  Aqueous sodium hydroxide = Red-brown ppt, insoluble in excess

  Aqueous ammonia = Red-brown ppt, insoluble in excess
• Test for zinc cation (Zn2+)


  Aqueous sodium hydroxide = white ppt, soluble in excess, giving a colourless solution

  Aqueous ammonia = White ppt, soluble in excess, giving a colourless solution.
• Gas test for ammonia (NH3)

  Turns damp red litmus paper blue
• Gas test for carbon dioxide?


  Limewater turns from colourless to milky
• Test for chlorine gas


  Bleaches damp litmus paper
• Test for hydrogen gas 


  'Pops' with lighted splint (squeaky pop)
• Test for oxygen gas


  Relights glowing splint
• Test for sulfur dioxide 


  Turns acidified aqueous potassium mangantage (VII) from purple to colourless
• Flame test for lithium?

  red
• Flame test for sodium?

  Yellow
• Flame test for potassium?


  Lilac
• Flame test for calcium?


  Orange-red
• Flame test for barium

  light green
• Flame test for copper (II)


  Blue-green
• Where is the independent variable plotted on a graph?


  IV on x-axis (horizontal)
• Where is the dependent variable plotted on a graph?


  DV on y-axis (vertical)
• Appearance of chlorine at rtp?


  Dense, pale-green gas - toxic (experiments involving chlorine gas should be done in a fume cupboard)
• Appearance of bromine at rtp?


  Deep-red liquid with red-brown vapour - posionous so experiments using bromine liquid should be done in a fume cupboard/with proper safety precautions
• Appearance of iodine at rtp?


  Greay solid with a purple vapour - poisnous so porpter safetu precautions should be taken.
• Does reactivity decrease or increase down the group 7/halogens?


  Reactivity of halogens decreases as you fo down the group (so chloirne is very reactive, whereas astantine is very unreactive.
• Does chlorine displace bromine?

  Yes - because it is above bromine in gorup 7.
• Carbonate (CO2-)


  Add dilute acid, effervescence, carbon dioxide produced
• Acidify with dilute nitric


  White precipitate (ppt.)
• Chloride (CH-)


  In solution
• Bromide (Br)


  In solution
• Iodide (I-)


  In solution
• Nitrate (NO3-)


  In solution