GENCHEM2 concepts

Bronsted-Lowry Acid

proton donor

Bronsted-Lorwry Base

proton acceptor

Arrhenius acid

Ionise in water to produce H⁺ ions

Arrhenius Base

Ionise in water to produce OH^_

Lewis Acid

Electron pair acceptor

Lewis Base

Electron pair Donor

Can an acid/base do one or more of being brownsted-lowry, arrhenius. lewis?

Yes. Pwedeng combination, pwedeng isa lang, pwedeng tatlo

this means there is a large amount of dissolved solute per unit volume

Concentrated

this means there is a small amount of dissolved solute per unit volume

Dilute

FULLY ionises in aqueous solution

Strong

Only PARTIALLY ionises in aqueous solution

Weak

Weal acids/base = reaction is —-

Reversible

Strong acid/base = reaction goes to —-

completion

Acid + Base yields

Salt + Water

Acid + Metal oxide yields

Salt + Water

Acid + Metal carbonate yields

Carbon dioxide + salt + water

Acid + Metal yields

Salt + Hydrogen

What is the substance that forms once an acid has donated a proton?

Conjugate base

What is the substance that forms that forms once a base has accepted a proton?

Conjugate acid

How to determine which element will donate a proton if 2 ACIDS are reacting?

The stronger acid will force the weaker acid to accept a proton

pH depends on —

Hydrogen ion concentration

the lower the pH, the stronger the —-

acid

Define pH

-log[H⁺]

In monoprotic solutions, since strong acids fully ionise in aqueous solution, we can conclude that [acid] = —?

[acid] = [H+]

moles of acid = moles of Hydrogen ions

concentration of acid = concentration of hydrogen ions

Note that this does NOT apply to diprotic or multiprotic solutions.

At 298K, Kw is equal to

1×10^-14

Dissociation is breaking of bonds = equilibria shifts to

right side (ENDOTHERMIC)

If Hydrogen ion concentration increases, pH —- & Kw —-

pH decreases, Kw increases

Above 298K, pure water pH is — 7, while Kw is — 1×10^-14

pH is less than 7

Kw is greater than 1×10^-14

Below 298K, pure water pH is — 7, while Kw is — 1×10^-14

pH is greater than 7

Kw is less than 1×10^-14

Pure water is ALWAYS considered to be neutral because [H+] = [OH-]

TRUE

If we know Kw and [OH-], what can we solve?

[H+], pH, pOH

because…

Kw=[H+][OH-]

Adding water to a solution REDUCES the ion concentration

True, therefore pH will change

If you add water to an acid, [H+] —-, and pH —-

[H+] decreases, pH increases (less acidic)

If you add water to a base, [OH-] —-, and pH ——.

[OH-] decreases, pH decreases (less basic)

The stronger the acid, the —- the Ka value

larger

Stronger acid = — Ka = — pKa

larger, smaller

What is the pH at equivalence point? What is mixed?

pH at equivalence point is 7. This is a strong acid-strong base reaction

What is the pH at equivalence point? What is mixed?

pH at equivalence point is <7. This is a strong acid-weak base reaction.

Because the salt that is produced is not exactly pH 7. Salt is a proton donor.

What is the pH at equivalence point? What is mixed?

pH at the equivalence point is >7. This is a weak acid-strong base reaction.

Salt is a proton acceptor.

What is the pH at equivalence point? What is mixed?

pH at equivalence is = 7. This is a weak acid-weak base reaction.

What is the pH at equivalence point? What is mixed?

pH at equivalence is = 7. This is a strong base-strong acid reaction.

What is the pH at equivalence point? What is mixed?

pH at equivalence is < 7. This is a weak base-strong acid reaction.

Salt is the proton donor

What is the pH at equivalence point? What is mixed?

pH at equivalence is > 7. This is a strong base-weak acid reaction.

Salt is a proton acceptor.

What is the pH at equivalence point? What is mixed?

pH at equivalence is = 7. This is a weak base-weak acid reaction.

The pH range over which the indicator changes color is pKa —

positive or negative 1

What needs to be mixed to create a buffer?

Weak acid + conjugate base

or

Weak base + conjugate acid

Ca(OH)₂ is a strong base if

concentration is less than or equal to 0.02M

Sr(OH)₂ is a strong base if

concentration is less than or equal to 0.01M

Ba(OH)₂ is a strong base if

concentration is less than or equal to 0.02M