[Part 4]- C8- the rate and extent of chemical change 💥

• [chemical] equilibrium, is a state in a reaction where the rate of the forward reaction, is equal to the rate of the reverse reaction. • [meaning, the forward and reverse reaction occur at the same rate]

• Le Chatelier’s principle states: when a system is at equilibrium, and a change is made to the conditions, the system [reaction] responds to counteract the changes.

• when the reactant concentration increases, more products will be formed. • this is because, of Le Chatelier’s principle therefore, it will counteract the change, by decreasing the concentration of the reactant.

• a system, can decrease the concentration of a reactant by: • increasing the rate at which the reactant is used up, and favouring the forward reaction. • this increases the rate of formation of the product- until equilibrium is established again

• if the product concentration increases, more reactants will be formed. • this is because, of Le Chatelier’s principle therefore, the system will counteract the change by decreasing the concentration of the product.

• a system can decrease the concentration of a product by: • increasing the rate at which the product turns into reactants, and favouring the reverse reaction, increasing its rate- until equilibrium is established again

• dynamic equilibrium is when the forward and reverse reactions are still occurring; the substances remain in balance [equilibrium]. • and [chemical] equilibrium, is a state in a reaction where the rate of the forward reaction, is equal to the rate of the reverse reaction.

• if a reversible reaction is exothermic in one direction, the reversible reaction is then endothermic in the opposite direction.

• as the forward reaction is exothermic: • when the forward reaction takes place, energy is released and the temperature of the system increases.

• Because every reversible reaction is different, some reversible reactions are exothermic in the forwards direction. • ; some are endothermic in the backwards reaction.

• if the backwards reaction is endothermic, energy is taken in and the temperature of the system decreases [when the reverse reaction takes place]

• pressure, is the force exerted over an area.

• pressure, affects reactions involving gases

• the pressure of a gas depends on the number of molecules

• if we increase the pressure on a reversible reaction, at equilibrium: • the position of equilibrium shifts to the side with the smaller number of molecules. • this is because an increase in pressure, favours the side with less molecules.

• if we reduce the pressure on a reversible reaction, at equilibrium: • the position of equilibrium, shifts to the side with the larger number of molecules.

• if the number of molecules is the same on both sides, changing pressure, will have no effect on the position of equilibrium

• if the forwards reaction produces more molecules of gas: • an increase in pressure will decrease the yield of products formed • ; a decrease in pressure, will increase the yield of product formed

• if the forwards reaction produces fewer molecules of gas: • an increase in pressure, will increase the yield of product formed • ; a decrease in pressure, will decrease the yield of product formed

• if the forward reaction is exothermic: • an increase in temperature, decreases the yield of product formed • ; a decrease in pressure, increases the yield of products formed

• if the forward reaction is endothermic: • an increase in temperature increases the yield of product formed; a decrease in pressure, decreases the yield of product formed

• if the temperature increases, the position of equilibrium will shift to reduce the temperature. • this is because of le chatelier’s principle therefore, the endothermic reaction will be favoured

• if the temperature decreases, equilibrium will shift to increase the temperature. • this is because of le chatelier’s principle so, the exothermic reaction will be favoured