Brønsted–Lowry Acid-Base Theory and Buffer Solutions

These flashcards cover key concepts related to Brønsted–Lowry acid-base theory, buffer solutions, and other associated chemical principles from the lecture notes.

The ion that causes a solution to be acidic is __.

H+ (hydrogen ion) or H3O+ (oxonium ion)

The equation for the ionisation of water can be written as __.

2H2O (l) ⇌ H3O+ (aq) + OH- (aq)

The physical factor that affects the value of Kw is __.

Temperature.

The equation used to calculate pKw is __.

pKw = -log Kw

If two solutions have a pH difference of 1, the difference in [H+] is __.

A factor of 10.

To find [OH-] from pH at 298K, you would calculate __.

[H+] and use [H+][OH-] = 1 x 10^-14.

When dealing with diprotic and triprotic acids, you need to multiply the concentration of the acid by __ to find [H+].

The number of protons.

Use Kw to calculate the [H+] from [OH-] in a strong alkaline solution and then apply __ to find pH.

pH = -log[H+].

The difference between concentrated and strong is that concentrated means __, while strong refers to __.

many mol per dm3; amount of dissociation.

Weak acids and bases __ in water and only partially dissociate into their ions.

Do not fully dissociate.

To work out the pH of a weak acid, use the equation for __ and then the equation for pH.

Ka.

pKa is used to make __ values more manageable.

Ka.

A titration is the addition of an acid/base of known titration to a base/acid of __ titration to determine concentration.

Unknown.

The equivalence point is defined as the point where __ has been added to just neutralize the acid.

The exact volume of base.

Around the equivalence point, the pH of the solution will show __.

A large and rapid change.

The end point of a titration is when __ changes colour.

The indicator.

A good indicator for a reaction should show a __ colour change and be distinct.

Sharp.

Methyl orange turns in acid and in alkali.

Red; yellow.

The colour of phenolphthalein in acid is and in alkali is .

Colourless; red.

The half-neutralisation point occurs when the volume added equals __.

Half the volume at the equivalence point.

An acidic buffer solution generally contains __ and a soluble salt of that acid.

A weak acid.

One way to achieve an acidic buffer solution is to neutralize half of a weak acid with __.

An alkali.

To calculate the pH of buffer solutions, use the __ of the weak acid.

Ka.

The buffer system that maintains blood pH at 7.4 involves __.

H+ + HCO3- ⇌ CO2 + H2O.

The difference in enthalpy changes of neutralisation values is due to __ energy absorbed by weak acids.

Less exothermic.