Chemistry

• Why are group eight elements unreactive? 


  They have filled outer shells and are stable
• Colour of copper oxide 


  black
• colour of copper sulphate


  blue
• sodium chloride 


  white
• calcium oxide 


  white
• magnesium chloride 


  white
• magnesium solution 


  colourless
• What colour are group one compounds 


  white dissolve to form colourless solution
• Group names?


  1 alkali

  2 alkaline

  7halogens

  8 noble gases

  0 noble gases - colourless
• fluorine 


  yellow gas
• chlorine 


  green yellow
• bromine 


  red brown
• iodine 


  grey black
• 11 gases 


  helium neon argon krypton hydrogen radon xenon flourine chlorine oxygen nitrogen
• 2 liquids 


  bromine mercury
• Who made the periodic table

  Mendeleev
• Differences between modern and old table

  left spaces for new elements , order of atomic weight , no noble gases , no block of transition elements
• Diatomic


  means 2 or more atoms bonded in a molcule
• composition of air


  oxygen 21%
• composition of air


  oxygen 21% nitrogen 78% co2 0.03%
• physical properties of oxygen

  colourless odourless tastless slightly soluble in water neutral
• catalyst 


  substance that speeds up a reaction but is never used up
• hydrogen peroxide


  oxygen + water
• test for oxygen


  apply glowing splint if splint relights gas is oxygen
• use of oxygen


  medicine welding increases flame temp
• metas burn to give

  basic oxides
• non metals burn to give

  acidic oxides
• redox


  when oxidation and reduction occur at the same time
• reduction


  removal of oxygen addition of hysrogen
• oxidation


  addition of oxygen removal of hydrogen
• test for hydrogen


  apply lighted splint if there is a squeaky pop gas is hydrogen
• equation 


  metal + acid = salt + hydrogen
• general observations for hydrogen

  bubbles heat released usually disappers colourless solution is produced
• properties of hyrdogen


  colourless odourless tasteless gas less dense in air not very soluble neautral
• acid rain

  • coal containing sufur is burned
• acid rain

  • coal containing sulfur is burned , burns to give sulfur dioxide, dissolves in water to give sulfourus acid, damages vegetation, corrodes buildings,
• acid rain solutions


  use catalytic converters bur less fossil fuels
• nitogen properties


  colourless tasteless odourless gas neutral
• uses of nitrogen


  food packaging coolant to freexe
• what does nitrogen only react with


  lightning