ChemH Unit 10 Part 1 Quiz

Acids

ph

Bases

ph>7, pink in phenolpthaline, blue on red litmus paper

Acid/Base Definition #1

Arrhenius: Focuses on ions produced in aqueous solution

Acids

Increase the concentration of H+ in water

Bases

Increase the concentration of OH- in water

Strong Acid

donates one H+ 100% of the time to a water molecule. Will be a completion reaction

Weak Acid

donates a small number of hydrogen ions to water, ionizes less than 100% of the time

6 Strong Acids that I NEED TO KNOW

HCl, HBr, HI, HNO3, H2SO4, HClO4

Ka

Acid ionization constant

Equilibrium Constant Ka

Will always have two ions on the top of the equation, with one of those being the hydronium ion. The denominator will always have one substance, the original acid molecule.

Strong bases

Solid hydroxides containing any group 1 metals or group 2 metals from calcium downward. These will dissociate completely in water. Will be completion reactions.

Weak bases

All other hydroxides.

Kb

Other substances which are not hydroxides can react by removing a H+ from a water molecule. Here, we use a Kb equation

Equilibrium Constant Kb

Will always have two ions on the top of the equation, with one of those being the hydroxide ion. The denominator will always have one substance, the original base molecule.

Acid/Base Definition #2

Brønsted: For reactions that don’t occur in water. Brønsted equations require ***both*** an acid and a base to be present in every equation, since every single reaction requires a giver and a receiver.

Brønsted Acid

Any structure which donates a hydrogen ion.

 Brønsted base

Any structure which accepts a hydrogen ion.

Brønsted Reactions

A Brønsted reaction may be either strong or weak, depending on how easily a hydrogen is transferred. To distinguish the forward and reverse reactions, the acid and base for the reverse reaction are called the **conjugate acid**and **conjugate base**. If a reaction establishes an *equilibrium*, it must be true that the *reverse reaction must also have one acid and one base*, since a hydrogen is transferred to get back to the original reactants.

Monoprotic Acid

An acid that can only donate a **single proton** per molecule.

Polyprotic Acid

An acid that can contribute **more than a single proton** per molecule.

Amphoteric substance

A substance that can either gain or lose a hydrogen ion

Kw

Self Ionization constant of water

Ph scale

Ranges from 0-14, 7 is neutral. Each 1 unit of pH represents changing H3O+ by a factor of 10.

6 Strong Bases I NEED TO KNOW

LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

Weak Acids I NEED TO KNOW

HCOOH, CH3COOH, CCl3COOH, HF, HCN, H2S, H2O

Weak Bases I NEED TO KNOW

NH3, N(CH3)3, C5H5N, NH4OH, H2O, HS-