Acid, Bases, and pH

Info

pH stands for the power of . The pH scale is a logarithmic scale, with 0 being acidic, and 14 being basic.

Numbers can go off the scale, it's just not common in consumer products

Table

The relative concentrations of (or ) and ions are as follows:

Acid	Equality	Base	Acid / Base
	>		acid
	<		base
	==		neutral

Models

"gRaDe 10"

Simplest theory; use this first

Definition

Acids dissolve (dissociate) in water (physical change)

Bases dissociate into hydroxide an equation with , acids dissociate into an equation with

Examples

Acids:

Bases:

Exceptions:
is basic, even though there's no

"GrAdE 11"

Definition

Acids react with water (chemical change)

Info

The "proton" refers to an ion (i.e , and is really just a proton).
Whoever has the proton is the acid, and whoever wants the proton is the base.

Acid

The donates the to the


Acid	Base	Reversible reaction	Conjugate base	Conjugate acid: hydronium

Base

The , which is more polar, donates an to the


Base	Acid	Reversible reaction	Conjugate base: hydroxide	Conjugate acid

Formulae

pH can be calculated using the following formulas:

Arrhenius Model:

Using the definition of log,

Bronstead-Lowry:

pOH Scale:

where the ions (, ) refer to their concentration in molarity (M)

Example

What is the pH of 2.5 M ?

solution
Because there are 2 hydrogen atoms,

Example

A chemist wants to make a 1.00L solution of HCl with a pH of 1.00. Calculate how many moles of HCl should be dissolved in the 1.00L.

solution