Chemistry

• What is an atom?

  The smallest particles that exist that make up an element
• What does saturated mean?

  a solution that will not dissolve any more solute at a certain temperature
• What gases are released when fuels are burned?

  .Carbon dioxide (when enough oxygen is present, complete combustion)

  .Water (vapour)

  .Carbon monoxide (when there is not enough oxygen present, incomplete combustion)

  .Sulfur dioxide (most fuels contain sulfur)

  .Oxides of nitrogen (formed at high temperatures because 78% of the air is nitrogen)

  .Particulates (consisting of soot and unburned fuels => happens when there is limited amount of air)
• What causes global warming and how?

  Carbon dioxide => it is a greenhouse gas which reduces the amount of heat lost from the Earth
• What causes global dimming and how?

  Particles => reduction in the amount of light reaching earth's surface because sunlight is reflected away
• What causes acid rain?

  Sulfur dioxide and oxides of nitrogen
• What are the two ways to ‘crack’ hydrocarbons?.

  -Passed over a hot catalyst 

  -Mixed with steam and heated to high temperatures
• What is the test for alkenes?

  Alkenes react with bromine water, turning it from orange to colourless.
•  What metals are less reactive than carbon?

  Zinc, Iron, Copper, Gold
• What metals are more reactive than carbon?

  Potassium, Sodium, Lithium, Calcium, Magnesium
• How is copper extracted?

  Smelting => heating copper ore very strongly in air to produce crude copper or electrolysis
• What is phytomining?

   Using plants to absorb metal compounds. The plants are burned to ash that contains the metal compounds.
• What is bioleaching?

   Using bacteria to produce leachate solutions that contain metal compounds
• What is electrolysis with copper?

  Positive copper ions are attracted to the negative electrode (cathode) where they gain two electrons and become copper atoms.
• What is displacement using scrap iron?

  Produces copper from the solution because iron is a more reactive metal and displaces it out of the solution.
•  Why are the current methods of extraction expensive?

  There are many stages in the process and alot of energy is needed.
• What does saturated mean?

   A solution that will not dissolve anymore solute at a certain temperature.
• What is an atom?

  The smallest particles that make up an element.
• We recycle metals because extracting them...

  • Uses limited resources
  • Is expensive in terms of energy