chemical analysis

• what is a pure substance?

  A substance that is made up of only one type of particle or element
• what is a mixture?

  A combination of two or more substances that are not chemically bonded.
• what is a formulation?

  a precise mixture with specific amounts of different substances designed for a specific purpose
• if a substance has a very sharp melting point,is it likely to be pure or a mixture?


  pure
• what is the flame test of copper?

  green
• what is the flame test of lithium?

  crimson
• what is the flame test of sodium?

  yellow
• what is the flame test of calcium?

  brick red
• what is the flame test of potassium?

  lilac
• can a flame test be used on a mixture?

  no,some flame colours are masked by others
• what is the colour precipitate of magnesium?

  white

  Mg(OH)2
• what is the colour precipitate of aluminium?

  white

  Al(OH)2
• what is the colour precipitate of calcium?

  white

  Ca(OH)2
• what is the colour precipitate of iron(II)?

  green

  Fe(OH)2
• what is the colour precipitate of iron(III)?

  brown

  Fe(OH)3
• what is the colour precipitate of copper(II)?

  blue

  Cu(OH)2
• what is the chemical test for carbonate?

  add an acid and bubble gas through limewater
• what is the observation of carbonate?

  limewater turns cloudy
• what is the chemical test of a sulfate?

  Add HCl

  Then BaCl2
• what is the observation of sulfate?

  white precipate
• what is a chemical test of halides(chloride,bromide,iodide)?

  add nitric acid

  then silver nitrate
• what is the observation of chloride?

  white precipitate
• what is the observation of bromide?

  cream preciptate
• what is the observation of iodide?

  yellow precipitate
• test for hydrogen?

  flame set in the sample
• observation of hydrogen?

  squeaky pop
• test for oxygen?


  put a glowing splint in the sample
• observation of oxygen?


  splint relights
• test for carbon dioxide?

  bubble the gas through lime water
• observation for carbon dioxide?

  limewater turns cloudy
• test for chlorine?

  place damp blue litmus in the sample
• observation of chlorine


  litmus paper is bleached white
• what additional test can be performed on Al(OH)3

  add excess NaOH and the precipitate re-dissolves
• describe flame emission spectroscopy?

  an element is heated(in a flame)it emits light at a particular frequencies.

  a light detector can identify all of the different frequencies that are emitted.
• what is the use of flame emission spectroscopy?

  used to identify elements in a sample.
• advantages of flame emission spectroscopy?

  quicker

  more accurate

  more sensitive(can detect tiny amounts)