Acid-Base Equilibrium and Solubility Equilibria in CHEM135

These flashcards cover key vocabulary and concepts related to acid-base equilibria and solubility equilibria from the CHEM135 lecture notes.

Autoionization of Water

The process where water molecules react with each other to form hydronium ions (H3O+) and hydroxide ions (OH-).

Kw

The ion product of water, equal to [H3O+][OH-], at 25°C it equals 1.0 x 10^-14.

Hydronium Ion (H3O+)

The ion formed when a water molecule gains a proton (H+).

Hydroxide Ion (OH-)

The ion formed when a water molecule loses a proton (H+).

pH Scale

A logarithmic scale used to specify the acidity or basicity of an aqueous solution, calculated as pH = -log[H3O+].

pOH

A measure of the hydroxide ion concentration in a solution, defined as pOH = -log[OH-].

pKa

The negative logarithm of the acid dissociation constant (Ka); a lower pKa indicates a stronger acid.

pKb

The negative logarithm of the base dissociation constant (Kb); a lower pKb indicates a stronger base.

Conjugate Acid-Base Pair

A pair of compounds that differ by a single proton (H+); for example, HCl and Cl-.

Percent Ionization

The ratio of the concentration of ionized acid to the initial concentration of acid, expressed as a percentage.

Monoprotic Acids

Acids that can donate only one proton (H+) per molecule in an acid-base reaction.

Diprotic Acids

Acids that can donate two protons (H+) per molecule in an acid-base reaction.

Polyprotic Acids

Acids that can donate more than one proton (H+) in a stepwise manner.

Solubility Product (Ksp)

An equilibrium constant for the dissolution of a sparingly soluble ionic compound.

Common Ion Effect

The reduction in solubility of an ionic compound by the presence of a common ion.

ICE Table

A table used to keep track of the Initial, Change, and Equilibrium concentrations of reactants and products.

Amphoteric

A substance that can act as both an acid and a base.

Weak Acid

An acid that does not fully dissociate in solution and has a small Ka value.

Weak Base

A base that does not fully dissociate in solution and has a small Kb value.

Strong Acid

An acid that completely dissociates in solution, yielding a high concentration of hydronium ions.

Strong Base

A base that completely dissociates in solution, yielding a high concentration of hydroxide ions.

what does ^H > 0 tell you

That it’s endothermic

What does ^H < 0 tell you

That it’s exithermic

Does spontaneous mean fast

No

If a reaction is spontaneous forward, is it spontaneous forward too

No the reverse is nonspontaneous

What’s endothermic

Heat is absorbed

Exothermic

Heat is releases

When temp increases, is it exothermic or endothermic

Exothermic

When temp decreases, is it exothermic or endothermic

Endothermic

For a reversible process is the Entropy of the universe = to or > 0

=

For a irreversible process is the entropy of the universe = to or > 0

>0

does more freedom to move = lower or higher entropy

higher entropy

Does a spontaneous process always increase the entropy of the universe

Yes

What is a microstate

A specific way particles can be arranged

What does more microstates mean

Higher entropy

Which state of matter almost always increases entropy

Gas

What a standard entropy, S•

It’s the absolute entropy of a substance at 1 atm and 25 degrees C

What does S• tend to increase with

Increasing Molar mass and increasing molecular complexity

When ^H is negative and ^S is positive what will ^G be and is it spontaneous

G will be negative and it will always be spontaneous

When ^H is positive and ^S is negative what will ^G be and is it spontaneous

G will be positive and it will always be nonspontaneous

What does ^G• =

-RTlnK

at equilibrium what is the value of of ^G

0

If Q>K does the reaction shift forward or backward

it shifts forward

If Q<K does the reaction shift forward or backward

Backward

If ^G• is negative, is K>1 or <1

K>1

Oxidation is

Loss of electrons

Reduction is

Gain of elections

What is the oxidation number of a element in its elemental form

0

Where does reduction occur

Cathode

Where are electrons consumed

Cathode

Where does oxidation occur

Anode

Where are electrons produced

Anode

What does the salt bridge maintain

It maintain neutrality

What does the salt bridge allow to move

It allows ions(not electrons) to move

What does SHE stand for

Standard hydrogen electrode

With More positive E• is it more likely to be oxidized or reduced

Reduced

With More negative E• is it more likely to be oxidized or reduced

Oxidized