fourths

• the relative formula mass of a compound is the sum of the relative atomic masses of all the atoms present in the formula
• an acid in aqueous solution is a source of hydrogen ions
• an alkali in aqueous solution is a source of hydroxide ions
• acid + base -> salt + water
• all sodium, potassium, and ammonium salts are soluble.

  all nitrates are soluble
• all chlorides are soluble with the exception of silver and lead (II) chloride
• all sulfates are soluble with the exception of barium, calcium, and lead (II) sulfate
• all carbonates are insoluble with the exception of sodium, potassium, and ammonium carbonates
• all hydroxides are insoluble with the exception of sodium, potassium, and calcium hydroxides
• an acid is a proton donor and a base is a proton acceptor
• alkali + acid -> water + salt
• carbonate + acid -> water + salt + carbon dioxide
• metal + acid -> salt + hydrogen
• test for hydrogen: lit splint, squeaky pop
• test for oxygen: glowing splint relights
• test for carbon dioxide: bubble through limewater, turns cloudy
• test for ammonia: red litmus paper, turns blue
• test for chlorine: damp litmus paper, bleaches
• flame test:

  • dip nichrome wire in concentrated hcl to remove impurities
  • dip wire into salt
  • hold in roaring bunsen burner flame
• flame test colours:

  • Li = red
  • Na = yellow
  • K = lilac
  • Ca = orange/red
  • Cu = blue/green
• to test for NH4, add sodium hydroxide (NaOH) and warm. if NH4+ ions are present, NH3 will form and this will turn red litmus paper blue
• add NaOH:

  • copper (II) ions = blue precipitate
  • iron (II) ions = green precipitate
  • iron (III) ions = brown precipitate
• halide ions tests

  add silver nitrate solution:

  • chloride ions: white
  • bromide ions: cream
  • iodide ions: yellow
• to test for sulfate ions, add barium chloride solution and a white precipitate will form
• to test for carbonate ions, add hcl and fizzing will occur
• add anhydrous copper (II) sulfate to a sample, if water is present it will turn from white -> blue
• a catalyst speeds up the rate of a reaction and is left chemically unchanged by the reaction. they work by providing an alternative pathway with a lower activation energy.