Unit 1.7

• Reversible reactions can go in either direction (forwards or backwards) depending on the conditions.
• Dynamic equilibrium refers to when the rates of the forward and backward reactions are the same.
• Macroscopic properties (properties that we can observe or measure) remain constant in an equilibrium reaction.
• Le chatelier's principle states that if a system at equilibrium is subjected to change, the position of the equilibrium will shift to minimise the effects of the change.
• The position of the equilibrium determines the proportion of products to reactants in an equilibrium mixture.
• Increasing the concentration of a reactant will shift the equilibrium to the opposite side.
• Increasing the pressure will move the position of the equilibrium to favour the side with fewer molecules/mols.
• Increasing the temperature will shift the equilibrium position to favour the endothermic reaction.
• A catalyst has no affect on the position if the equilibrium, instead equilibrium is reached faster.
• Kc is the equiequilibrium constant. It is a constant value at a constant temperature.
• If Kc is larger than 1, than the equilibrium mixture contains a higher concentration of products to reactants, so the equilibrium is to the right. The larger the Kc value, the more to the right the equilibrium is.
• If Kc is smaller than 1, then there is a smaller concentration of products to reactants, so the equilibrium is to the left. The smaller the Kc value, the more to the left the equilibrium is.
• An acid is a proton (H+) donor.
• A base is a proton (H+) acceptor.
• A strong acid fully dissociated into H+ ions and anions
• A weak acid only partially dissociated to H+ ions and anions in an aqueous solution.
• A concentrated acid contains more acid molecules than water molecules.  
• A dilute acid contains a large amount of water and a small amount of acid molecules.
• pH = -log(H+)
• Universal indicator is the simplest way to measure pH, however for more accurate measurements use pH meters.
• Neutralisation occurs when an acid and base react to produce a salt and water.