Chemical analysis

• Pure substance is something that only contains one compound or element throughout the whole substance
• You can test the purity of a sample by measuring its melting or boiling point and comparing it with the melting or boiling point of the pure substance
• Impurities in your sample will lower the melting point and increase the melting range of your substance. it will also increase the boiling point and result in your sample boiling at a range of temperatures
• Formulations are mixtures with exact amounts of components
• Formulations can be found in cleaning products, fuels, cosmetics, fertilisers
• Rf = distance travelled by substance B/ distance travelled by solvent A
• Test for chlorine

  Chlorine bleaches damp litmus paper white
• test for oxygen

  If you put a glowing splint inside a test tube containing oxygen, the oxygen will relight the glowing splint
• Test for carbon dioxide

  Bubbling carbon dioxide through an aqueous solution of calcium hydroxide causes the solution to turn cloudy
• Test for hydrogen

  If you hold a lit splint at the open end of a test tube containing hydrogen, you will get a squeaky pop. noise comes from hydrogen burning quickly with oxygen in the air to form h2O