Reversible reactions, Ammonia and Haber process

• What are many reactions, such as burning fuel?


  Irreversible
• What is an irreversible reaction?


  A reaction that goes to completion and cannot be reversed easily
• What type of reaction is different to an irreversible reaction?


  Reversible
• What is a reversible reaction?


  The products can react to produce the original reactants again
• What are products?


  A substance formed in a chemical reaction
• What are reactants?


  A substance that reacts with another substance to form a product during a reaction
• What is not used when writing reversible reactions?

  A normal one-way arrow
• What is used instead of a normal arrow for a reversible reaction?


  Two arrows, each missing half an arrowhead
• What directions do the arrows point in a reversible reaction?

  Top points right, bottom points left
• What is an example of a reversible reaction?

  ammonium chloride ⇌ ammonia + hydrogen chloride
• What does the reversible equation for ammonium chloride show?


  That ammonium chloride can break down to form ammonia and hydrogen chloride and ammonia and hydrogen chloride can react together to form ammonium chloride
• What is the reversible reaction including anhydrous copper sulfate and blue hydrated copper sulfate?

  anhydrous copper(II) sulfate + water ⇌ hydrated copper(II) sulfate
• What is anhydrous copper sulfate?


  Copper sulfate with the water removed
• What does anhydrous copper sulfate react with to form hydrated copper sulfate?


  Water
• What kind of reaction is removing water from copper sulfate?


  Endothermic
• If a reaction starts as endothermic, what will the reverse reaction be?

  Exothermic
• If a reaction starts as exothermic, what will the reverse reaction be?

  Endothermic
• The amount of energy absorbed in the forward process is exactly the same as the amount of energy released in the reverse process.
• What form is anhydrous copper sulfate?


  White crumbly powder
• What is the chemical symbol for ammonia?

  NH3
• What is ammonia important in?

  The manufacturing of fertilisers
• What is ammonia?


  An important raw material
• What is some ammonia converted into?

  Nitric acid
• Why is some ammonia converted into nitric acid?


  For the manufacture of fertilisers and explosives
• What is ammonia a useful ingredient in?

  Cleaning fluids
• Ammonia is a vital route by which nitrogen in the air can be made available to plants to enable them to build protein molecules.
• What can't plants use directly from the air?

  Nitrogen
• What form of nitrogen do plants need?


  Nitrogen compounds dissolved in water, which can be absorbed through their roots.
• What type of gas is ammonia?

  Alkaline
• What would happen without synthetic, ammonia-based fertilisers?

  The world wouldn’t be able to grow enough food to feed it’s population
• What is the test for ammonia?

  Litmus paper
• What happens when ammonia reacts with damp red litmus paper?


  It turns blue
• Where are ammonium ions found?

  In ammonium compounds e.g ammonium chloride
• How are ammonium ions identified?

  By heating a solution of the ions with sodium hydroxide
• What is damp red litmus paper the test for?

  Ammonia gas
• What are the raw materials needed to make ammonia?

  Hydrogen and Nitrogen
• How is hydrogen obtained?

  By reacting a natural gas with steam, or from cracking oil fractions
• How is nitrogen obtained?


  From the air
• What percentage if air is nitrogen?

  78%
• What is the Haber process?

  The process of making ammonia from hydrogen and nitrogen