acids

• acids (H+)


  any substance that forms an aqueous solution with a ph less the seven
• three main acids


  sulfuric acid

  nitric acid

  hydrochloric acid
• When acid molecules are added to water and split apart, we say that they 'ionise' or 'dissociate'. These two words both mean the same thing. 
• The concentration of an acid refers to the number of moles of acid molecules per unit of volume.
• strong acids


  sulfuric acid, nitric acid and hydrochloric acid, are all strong acids

  this means that when dissolved in water every molecule splits up into its ions- they are completely ionised
• weak acid


  ethanol, citric acid , and carbonic acid are weak acids.

  this means that only a percentage of their molecules split up into ions when dissolved in water- they are partially ionised
• the stronger the acid the lower the ph
• concentration


  how much of a substance there is dissolved in water
• • more concentrated acids have lots of acid in a small volume of water
  • less concentrated acids have little acid in a large volume of water
• To work out the formula of the salt, take the positive ion from the base, such as sodium from sodium oxide (Na2O), and the negative ion from the acid, such as chloride from hydrochloric acid (HCl), and combine them together.
• acids + metals


  acids react with some metals to form salts and hydrogen gas

  magnesium + hydrochloric acid -> sodium chloride + hydrogen
• 
  

  acids + metal hydroxide

  acids react with metal hydroxides to form salts and water

  • hydrochloric acid + sodium hydroxide -> sodium chloride + water

  the ionic equation for this reaction is always:

  H+ +OH- -> H2O
• acids + metal oxides 


  acids react with metal oxides to form salts and water

  • hydrochloric acid + sodium oxide -> sodium chloride + water
• acids + metal carbonates


  acids react with metal carbonates to form salt, water and carbon dioxide

  • hydrochloric acid + sodium carbonate -> sodium chloride + water + carbon dioxide
• HYDROCHLORIC ACID (HCL)

  • ions formed in solution - H+ and CL-
  • metal chloride
  • eg. sodium chloride NaCL
• NITRIC ACID (HNO3)

  • H+ and NO3-
  • metal nitrate
  • eg. sodium nitrate - NaNO3
• SULFURIC ACID(H2SO4)

  • 2H+ and SO4^2-

  metal sulfate

  eg. NaSO4