Honors Chemistry- Acids and Bases

Acids formula

Starts with H, and can end with COOH-

Bases formula

Ends with OH-, ends with CO3, or has an NH3 group

What does the strength of an acid/base deal with?

The dissociation, NOT HOW ACIDIC IS IT

Strong acids and special property

They ionize 100%, and are therefore not at EQ. The rule only for strong acids is that the (HX)=(H+)

Weak acids and special property

They do not dissociate entirely, rather partially ionize, so therefore the reaction can be at EQ. The special property is that (HX)>(H+)

Acidity

The measure of how much H+ is in the water

Technically, all solutions contain H+ and OH-, why?

Because of the auto-Ionization of water

Neutral solution

H+=OH-

Acidic solution

H+>OH-

Basic solution

H+<OH-

pH

Measure of H+ in a solution

pOH

measure of OH- in a solution

OH- on a pH scale

0-7 is more basic, and 7-14 is more acidic

H+ on a pH scale

0-7 is more acidic, whereas 7-14 is more basic

pH and pOH equations

For both, take the negative log of the concentration of either H+ or OH-

H+ and OH- concentrations

Use the base 10 and raise it to the negative of either pH or pOH

H+ x OH- always=

1×10^-14

pH+pOH always=

14

As H+, what happens to (OH-), pH, pOH, and acidity?

(OH) decreases, pH decreases, pOH rises, and acidity rises

SA/SB neutralization reactions

Acids react with bases ALWAYS until something runs out

Double replacement reaction: Acid Base NEUTRALIZATION

First and last ions will pair up, the two in the middle will pair up. Balance the charges once done to determine the salt formula. The salt formula can contain alkaline metals (like Na, K, Li). Once charges are balanced, then balance the reaction

Arrhenius Acid/Base

Substance that adds H+/OH- ions to a solution

Bronsted-Lowery acids

Proton H+ donors

Bronsted-Lowery bases

Proton H+ acceptors

Most important detail of Bronsted-Lowery situations

Keep track of charges!!! Acceptors gain 1+, receivers get 1-

Bronsted-Lowery reactions are ALL

Reversible, so the H+ ion can keep getting bounced back and forth between the two chemicals…

Bronsted-Lowery reactions will have conjugates, meaning…

Acids become bases and bases become acids in the reverse reaction

IMPORTANT RULE ABOUT CONJUGATES

They are NEVER on the reactants side

How do an acid and conjugate base pair differ?

They differ only by an H+

How do acids become the conj base?

they will LOSE ONE H+

How do bases become the conj acid?

they will GAIN ONE H+

Amphoteric

Substances that can act as both an acid and a base depending on the environment and what you react it with

Percent ionization(weak) And what is the formula?

Illustrates the percentage of acid molecules that will be dissociated into their ions at a given time. Using the formula (H+)/(HA) X 100

Ka

Acid ionization constant(FOR WEAK)

What does Ka tell us?

Bigger value=More ionization=Stronger Acid(Direct relationship)

Steps to a typical Ka problem

Write the reaction and BALANCE!, write Ka expression, make an ice table and consider ratios, calculate equilibrium concentrations.

Ka Table

A table that lists the ionization constants of various weak acids, allowing for easy comparison of their strengths.

If you know the Ka of an acid, you can find the Kb of its conjugate base and vice versa using

Ka x Kb= 1×10^-14

The stronger the acid, the weaker its...

CONJ base

Salt hydrolysis

some ionic compounds will make a solution acidic or basic when dissolved in water

Special rule for weak acids in salt hydrolysis

Since base partially ionizes, the H+ can also transfer on the products side

Bases in Disguise(Anions)

Conjugates of weak acids will make a solution basic

The conjugates of strong acids “6 strong” and what do they do?

Cl-, Br-, I-, ClO4 -, NO3 -, SO4 2-, they always neutralize bases

Acids in Disguise(Cations)

Conjugates of weak bases will make a solution acidic, but for metals, only if they have charges 3+ or higher. Because charges of 1 and 2 are not as strong, and one of the H bonds on H2O will instead go away

What does 2 neturals mean?

No reaction with H2O