hsc-chemistry-notes: MODULE 5: EQUILIBRIUM AND ACID REACTIONSStatic and dynamic equilibrium ● Model static and dynamic equilibrium and analyse the difference between open and closed ● Analyse examples of non-equilibrium in terms of entropy and enthalpy → Combustion → Photosynthesis ● Collision theory and reaction rate ● Dynamic equilibrium: Reversible; a reaction that proceeds in the direction of reactants and products. Products once formed can react again to reform the reactants. ● Static equilibrium: Irreversible eg combustion reactions ● Open system: Matter and energy can be exchanged with surroundings ● Closed system: Only exchanges energy with surrounding Equilibrium and collision theory ● Once products are formed: → Collisions between product particles can result in reactions re-formed ● Eg. Production of ammonia from hydrogen gas and nitrogen gas N2(g) + 3H2(g) = 2NH3(g) → 1 mol of nitrogen gas + 3 mol of hydrogen gas in closed system → Expecting 2 mols of ammonia to be formed but reaction seems to stop → Reactants and products cannot escape → Reversible reactions in a closed system reach a point where a forward reaction and rate of reverse reaction are equal → Nitrogen and hydrogen gas molecules collide to form ammonia → Concentration decreases in gas → Frequency of collisions decrease → Rate of production of ammonia decreases