10. 1, arrhenius acids and bases + pH, 12/5/25

Simplest and most limited definition of acid

Acid is a substance that dissolves and dissociates in water to form aqueous hydrogen ions, H+ (aq)

Simplest and most limited definition of base

Base is a substance that dissolves and dissociates in water to form aqueous hydroxide ions, OH- (aq)

do acids have be ionic?

no, ie. HCl is not ionic but instead highly polarized which allows it to form ions in water. Water tears apart different elements in HCl to form ions.

strong acid

Completely dissociates (ionizes: forma ions) in water

Strong base

Completely dissociates in water

Weak acid

does not ionize completely

Weak base

Does not dissociate completely

Electrolyte

Ahh substance that dissolves in water and can conduct electrical through ions

Types of electrolytes

Strong and weak electrolytes

pH scale is calculated based on

Based on hydrogen ion concentration, p is a function of H+

pH scale 0

• [H+] = 1 M (concentration of H+ is one molar)

• Most acidic

pH 14

• [OH-] = 1 M (concentration of hydroxide ions is one molar)

• Most basic

can you have negative pH or greater than 14?

Yes

Square brackets in chemistry [H+ (aq)]

square brackets means molar concentration or molarity

[H+][OH-] = constant

Concentration of hydrogen ions times the concentration of hydroxide ions equals a constant number that cannot be zero

Properties of [H+] and [OH-]

• cannot be zero

• If one increases, the other must decrease

• pH of 7 is where they are neutral, so [H+] = [OH-], they are balanced but always present

Ionization

Process of forming ions

Dissociation

Process in which ions break apart when dissociate in solution

Concentration of H+ in dilute solution of a strong acid =

Concentration of the acid

Concentration of OH- in dilute solution of a strong base =

Concentration of the base

Why is ammonia a base?

NH3 (aq) + H2O (l) ←> NH4+ (aq) + OH- (aq)