Chapter summary

Chapter summary

Presentation: VPenn

• The polar nature of water means that ionic compounds dissociate easily in aqueous solution into their component ions.

• Dissociation is the process in which solid ionic crystals are broken up into ions when dissolved in water.

• Hydration is the process where ions become surrounded with water molecules.

• Conductivity is a measure of a solution's ability to conduct an electric current.

• An electrolyte is a substance that contains free ions and is therefore able to conduct an electric current. Electrolytes can be divided into strong and weak electrolytes, based on the extent to which the substance ionises in solution.

• A non-electrolyte cannot conduct an electric current because it does not contain free ions.

• The type of substance, the concentration of ions and the temperature of the solution affect its conductivity.

• There are three main types of reactions that occur in aqueous solutions. These are precipitation reactions, acid-base reactions and redox reactions.

• Precipitation and acid-base reactions are sometimes known as ion exchange reactions. Ion exchange reactions also include gas forming reactions. Ion exchange reactions are a type of reaction where the positive ions exchange their respective negative ions due to a driving force.

• A precipitate is formed when ions in solution react with each other to form an insoluble product. Solubility rules help to identify the precipitate that has been formed.

• A number of tests can be used to identify whether certain anions (chlorides, bromides, iodides, carbonates, sulphates) are present in a solution.

• An acid-base reaction is one in which an acid reacts with a base to form a salt and water.

• A redox reaction is one in which electrons are transferred from one substance to another.