Topic 5

• The mass of product obtained from a reaction. It is normally less than the theoretical yield due to incomplete reactions, side reactions and loss of product in transfer.

  Actual yield
• A metal compound made by combining two or more metals together. This process is carried out to give the material greater strength or resistance to corrosion.

  Alloys
• The measure of the amount of starting materials that end up as useful products.

  Atom economy
• Equal volumes of difference gases will contain the same number of molecules.

  Avagadro’s Law
• A secondary product made in the reaction of something else.

  By-product
• A cell which converts chemical energy to electrical energy. They are made up of two metal electrodes connected by an electrolyte. The cell produces a voltage until one of the reactants is used up.

  Chemical cell
• The destruction of materials by chemical reactions with substances in the environment. For example, iron rusts when exposed to water an oxygen.

  Corrosion
• The process of coating a metal with a thin layer of another metal by electrolysis to improve the metal’s corrosion resistance or to improve the metal’s appearance.

  Electroplating
• A chemical added to soil to increase the fertility, allowing crops to grow more effectively. They generally contain compounds of nitrogen, potassium and phosphorus.

  Fertiliser
• An electrochemical cell which continuously produces a voltage when supplied with a fuel and oxygen. The fuel donates electrons at one electrode and oxygen gains electrons at the other electrode.

  Fuel cell
• A fuel cell in which hydrogen and oxygen are the reactants used to produce a voltage. Water is the only product.

  Hydrogen-oxygen fuel cell
• The volume occupied by one mole of gaseous molecules, 24dm^3 at room temperatures.

  Molar volume at RTP
• The percentage ratio of the actual yield of product from a reaction compared with the theoretical yield.

  Percentage yield
• The protection of iron or steel against corrosion by using a more reactive metal. Zinc is often used as a sacrificial metal.

  Sacrificial protection
• The maximum possible mass of product that can be obtained from a reaction.

  Theoretical yield
• A metal found between Group 2 and 3 of the periodic table. Typical properties include high melting points, high densities, form coloured compounds and catalytic activity.

  Transition metal