Topic 4 (chemical changes)

• what is a catalyst?

  catylists lower the activation energy of a reaction. they provide an alternative pathway to the product
• acid + metal carbonate


  salt + water + hydrogen
• Will a strong or weak acid completely ionise?

  Strong acid
• what happens to the strength of acids with more H ions?

  Increases
• how to find the limiting factor?

  number of moles in the substances

  look at molar ratio
• what is the sign for a reversible reaction?


  ⇌
• what is a base?

  anything that can neutralise an acid. all bases are alkaline but not all alkalis are bases
• what is a ore?

  a rock that has enough of a metal to make it economical to extract
• What does OIL RIG stand for?

  OIL RIG stands for Oxidation Is Loss of electrons, Reduction Is Gaining electrons
• How to form crystls from sulphuric acid and copper oxide?


  measure 40cm3 of sulphuric acid in a measuring cylinder and add to a 100cm3 beaker

  set up a tripod, gauze and heatproof mat put the beaker on and gently heat till almost boiling and remove fro heat

  add CuO until it is in excess

  filter using filter paper and funnel

  set up water bath using a 250ml beaker and heat on the tripod and gauze

  transfer the filtrate into an evaporating basin and heat

  when crystals start to from stop heating and leave to dry in a warm dry place
• Metal + acid

  Salt and hydrogen
• What is an electrolyte?

  a solution through which ions can flow