Chemistry Chapter 20-Chemistry Chapter 20-2121

Acids and BasesAcids and Bases

Electrolytes: Solutions that conduct electrical current

easily.

Aqueous solutions of acids and bases are electrolytes.

Ionic solids that dissolve in water are electrolytes.

The ammeter measures the flow of electrons (current) through the circuit.

If the ammeter measures a current, and the bulb glows, then the solution conducts. (Electrolyte)

If the ammeter fails to measure a current, and the bulb does not glow, the solution is non-conducting. (Non-electrolyte)

Electrolytes: The ability of a solution to conduct an electric current.

NaCl(s) Na+(aq) + Cl-

(aq)

Dissociation: Water surrounds ions and dissolves them.

Dissociation equation:

Dissociation of HClDissociation of HCl

HCl H+ + Cl-Dissociationequation.

GeneralDissociationequation.

HA H+ + A-

A- represents the anion

ClH H C lClH

Basic definition:

Acids:Produce hydrogen ions, H+ , when dissolved in

water.

Bases: Produce hydroxide ions, OH-, when dissolved in water.

Acid-Base Neutralization

Acid + Base Water + Salt

HCl + NaOH HOH + NaClH2O

Some Properties of AcidsSome Properties of Acids

Acids taste sour Acids react with certain metals to produce hydrogen gas.

2 HCl(aq) + Mg(s) H2(g) +MgCl2(aq)

Acids effect indicators Blue litmus turns red Phenolphthalein turns colorless Methyl orange turns red

Acids Effect on Indicators

Blue litmus paper turns red in contact with an acid.

Bases Effect on Indicators

Red litmus paper turns blue in contact with a base. Phenolphthale

in turns purple in a base.

pH Indicator

s and theirranges

Naming AcidsNaming Acids• Acids without oxygen:

Hydro_______ic acid

HF =HF =

HCl =HCl =

HBr =HBr =

HCN =HCN =

Hydrofluoric acid

Hydrochloric acid

Hydrobromic acid

Hydrocyanic acid

CN- = cyanide anion

HH22S =S =Hydrosulfuric acid

HI =HI = Hydroiodic acid

Naming AcidsH+ + (anions with oxygen)

Naming AcidsH+ + (anions with oxygen)

• Acids with oxygen: “ate-ic ite-ous”Anion name Acid name

____ate ____ic acid

___ite ___ous acid

HNO3 =

Anion NO3-1 = nitrate

HNO2 = Nitr__?__ acid

Nitrous acid

Nitr__?__ acid

Nitric acid

Anion NO2-1 = nitrite

Naming AcidsH+ + (anions with oxygen)

Naming AcidsH+ + (anions with oxygen)

Formula H+ with Anion Acid name

H2SO4 Sulfuric acid

2H+ + SO32- = sulfite

HC2H3O2

2H+ + SO42- = sulfate

H2SO3 Sulfurous acid

H+ + C2H3O2-1 = Acetate Acetic acid

H3PO4 3H+ + PO43- = PhosphatePhosphoric acid

H2CO3 2H+ + CO32- = Carbonate Carbonic acid

Naming AcidsH+ + (series of Cl and O)

Naming AcidsH+ + (series of Cl and O)

Formula H+ with Anion Acid name

HCl Hydrochloric acid

H+ + ClO-1 = hypochlorite

HClO2

H+ + Cl- = Chloride

HClO Hypochlorous acid

H+ + ClO2-1 = Chlorite Chlorous acid

HClO4 H+ + ClO4-1 = perchlorate Perchloric acid

HClO3 H+ + ClO3-1 = Chlorate Chloric acid

Hypo = less oxygen

Per = more oxygen

Naming BasesSame method as naming ionic

compounds

Naming BasesSame method as naming ionic

compoundsFormula Cation with OH- Base name

NaOH Sodium hydroxide(Lye)

Na+ + OH-

KOH Potassium hydroxide K+ + OH-

Ca(OH)2 Calcium hydroxide(Lime)

Ca2+ + 2 OH-

Mg(OH)2

Magnesium hydroxide(Milk of magnesia)

Mg2+ + 2 OH-

Al(OH)3 Aluminum hydroxide Al3+ + 3 OH-

NH3 Ammonia(common name)

(No ions)

Molecules that contain nitrogen are weak bases.

Acids Acids Have a pH Have a pH less than less than

77

Bases Bases have a pH have a pH

greater greater than 7than 7