chemical reactivity

strong acid meaning

an acid that completely dissociates in an aqueous solution, releasing the maximum possible number of hydrogen ions

weak acid meaning

an acid that partially dissociates in an aqueous solution, releasing a relatively few number of hydrogen ions

strong base meaning

a base that completely dissociates in an aqueous solution, releasing the maximum possible number of hydroxide ions

what does a solution’s conductivity depend on

the concentration of freely moving charged particles present in the solution, e.g. electrons or ions

what does pH measure

the concentration of hydrogen ions - lower pH means more hydrogen ions, e.g. H3O-H2O-OH

how are the strength, conductivity and pH of solutions connected

the stronger a acid/base is, the more it dissociates, the more ions are in the solution. The more ions there are, more reactions happen (higher rate of reaction) and it’s more conductive.

Kc expression

Kc = Products/reactants

dynamic equilibrium

the forward and reverse reaction rates are equal

the equilibrium constant

K - a value that indicates the relative amount of products and reactants at equilibrium

le chatelier’s principle

increasing the pressure, temperature or concentration favours the reaction that produces fewer moles of gas particles. decreasing these things favours the reaction that produces more moles of gas particles

endothermic and ±Kc

absorbing heat energy, +Kc

exothermic and ±Kc

releasing heat energy, -Kc

amphiprotic

can act as either an acid or base

conjugate pairs

two chemicals that are only different because of a hydrogen ion

the effect increasing the pressure of an all gas system would have on a equilibrium position

the system is unable to respond to decrease the pressure because both sides of the equation are all gaseous molecules, and the position of the equilibrium is unaffected

collision theory

reactant particles need to collide with enough energy and in the correct orientation to react

if the Kc value is smaller than your calculated one…

the forward reaction is favoured

if the Kc value is bigger than your calculated one…

the backward reaction is favoured

when working out if a substance has a high/low pH…

add it to H2O (NH4/NH3 are tricky)

equilibrium equation for NH4/NH3 (use ⇌)

NH4+H2O⇌NH3+H3O