what does the value of the equilibrium constant indicate
the position of the equilibrium
what happens to equilibrium in an exothermic reaction when the temperature is increased
the equilibrium moves to favour the production of the reactants. The yield of products decreases
what happens to equilibrium in an endothermic reaction when the temperature is decreased
the equilibrium moves to favour the production of products. The yield of products increases
what condition has an impact on the vale of K constant
Temperature
what does amphoteric mean and give an example
amphoteric describes a substance which can react as an acid and a base.
an example of this would be water
what is an acid
a substance which donates a proton and form a conjugate base
what is a base
a substance which accepts a proton and forms a conjugate acid
what does the salt of a strong acid and base form in water
a neutral solution
what does the salt of a weak acid and strong base form in water
a alkaline solution
what does the salt of a strong acid and weak base form in water
an acidic solution
what is a buffer
a buffer is a solution of which the pH remains constant when small amounts of acid or base are added
what is an acidic buffer
consist of a weak acid and one of its salts
what is a basic buffer
consists of a weak base and one of its salts
what happens when acid and base are added to acidic buffer
ACID
will react with ions of the salt to be converted back into the salt
BASE
will react with the H+ ions to neutralise and equilibrium will then move to replace the lost H+ ions
what happens when acid and base are added to a basic buffer
ACID
will combine with OH- ions to neutralise and equilibrium will move to replace lost OH- ions
BASE
will react with the ions of the salt to be converted back into salt
what is an indicator
weak acid which changes colour depending on the pH of the solution,
what is the standard state of a substance
1 atmosphere
298 K
what is standard enthalpy of formation
the enthalpy change when one mole of a substance is formed from elements in their standard states.
what is entropy
measure of the degree of disorder of the system
what has the lowest and greatest value of entropy
lowest - solids
greatest - gases
what happens to entropy as temperature increased
entropy increases
what is the entropy value of a perfect crystal
0K
when is a reaction said to be feasible
when the ^G between reactants and products is negative
Under non-standard conditions when is a reaction feasible
if ^G is negative
what is the value of ^G at equilibrium
0
what does the rate of reaction depend on
the concentration of reactants
what is zero order reaction
when the rate does not change as the concentration is changed
what is a 1st order reaction
when doubling the concentration doubles the rate
what is a 2nd order reaction
when doubling the concentration quadruples the rate
what is the rate of reaction dependant on
dependant on the slowest step which is called the rate determining step
how can the rate of reaction be determined
the rate can only be determined experimentally
What happens to the water equilibrium:
NH4Cl - Cl + NH4+
the ammonium ions combine with the OH- ions forming molecules of the weak alkali, ammonium hydroxide. To replace the lost OH- ions the equilibrium moves to the right. This gives an excess of H+ ions resulting in an acidic solution.
what happens to the water equilibrium:
CH3COONa - CH3COO- + Na+
ethanoate ions combine with the h+ ions to form molecules of the weak acid, ethanoic acid. To replace lost H+ ions the water equilibrium moves to the right. This produces an excess of OH- ions resulting in an alkaline solution
