Chemistry Test Notes- TEST I

An ELECTROLYTE is an aqueous solution that can conduct electricity.

They include ACIDS, BASES, and SALTS.

WATER in its pure form is a poor electrolyte, although its minerals and vitamins make it a decent conductor.

There are several theories presented about acids and bases:

ARRHENIUS noted that ACIDS produce H+ when reacted, and BASES produce OH-.

BRONSTED-LOWRY theory points out that ACIDS are proton donors, and BASES are proton acceptors. In essence, the two are the fundamentally the same because H+ is a bare proton.

LEWIS classifies ACIDS as an e- pair acceptors, and BASES as e- pair donors.

An ACID gives away a proton to become a CONJUGATE BASE.

A BASE accepts a proton to become a CONJUGATE ACID.

Sample Reaction:

HCl     +      H20 -> Cl-     +      H3O+ (HYDRONIUM ION)

Acid            Base      C.Base      C.Acid

NH3     +     H20   -> NH4+     +     OH-

Base           Acid       C.Acid           C.Base

(TIP: H20 can be either acid or base; you must choose according to the other reactant.)

AMPHOTERIC means either ACID or BASE; WATER is amphoteric.

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PROPERTIES of ACIDS:

Contain H+ with polyatomic ion or nonmetal

ORGANIC ACIDS

Carboxyl Group = COOH

FORMIC ACID -> HCOOH

ACETIC ACID -> CH3COOH (formed by adding H to ACETATE).

CITRIC ACID   -> found in citrus fruits

MALIC ACID    -> found in apples

LACTIC ACID  -> found in milk, and in sore muscles

ASCORBIC ACID -> Vitamin C

SALICYLIC ACID -> found in aspirin

INORGANIC ACIDS-

BINARY:

2 elements, H+ with a nonmetal

They are named:

HYDRO + STEM + ACID

HCl -> HYDROCHLORIC ACID

H3P -> HYDROPHOSPHORIC ACID

TERNARY:

"STEMIC" ACIDS are the most common.

They consist of H+ attached to an unmodified polyatomic ion (-ate).

ClO3 -> HClO3 -> Chloric Acid

NO3 -> HNO3 -> Nitric Acid

SO4 -> HSO4 -> Sulfuric Acid

CO3 -> HCO3 -> Carbonic Acid

PO4 -> HPO4 -> Phosphoric Acid

"PER-STEM-IC" ACIDS are made by adding 1 Oxygen to the acid.

ClO4 -> HClO4 -> Perchloric Acid
NO4 -> HNO4 -> Pernitric Acid
SO5 -> HSO5 -> Persulfuric Acid
CO4 -> HCO4 -> Percarbonic Acid
PO5 -> HPO5 -> Perphosphoric Acid

"STEM-OUS" ACIDS are made by subtracting 1 Oxygen from the acid.

ClO2 -> HClO2 -> Chlorous Acid
NO2 -> HNO2 -> Nitrous Acid
SO3 -> HSO3 -> Sulfurous Acid
CO2 -> HCO2 -> Carbonous Acid
PO3 -> HPO3 -> Phosphorous Acid

"HYPO-STEM-OUS" ACIDS are made by subtracting 2 Oxygens from the acid.

ClO -> HClO   -> Hypochlorous Acid
NO -> HNO   -> Hyponitrous Acid
SO2 -> HSO2 -> Hyposulfurous Acid
CO -> HCO -> Hypocarbonous Acid
PO2 -> HPO2 -> Hypophosphorous Acid

BASES

Properties of Bases:

Contain Hydroxide (OH)^- polyatomic ion + Metal or a poly⁺

Name a Base by adding “Hydroxide to the name of the positive element

Ex: KOH -> Potassium Hydroxide

       Ca(OH)₂ -> Calcium Hydroxide

       AgOH -> Silver Hydroxide

       CuOH -> Copper I Hydroxide

       Cu(OH)₂ -> Copper II Hydroxide

ANAHYDRIDE

     A substance that when added to H₂O will form an Acid or Base

Acids

      Non-Metal + Oxygen

     H₂SO₄ <-> H₂O + SO₃

     H₂SO₄

   -H₂   O

----------

         SO₃

Anahydride equations are reversible (Hydrate and Dehydrate the Acid/Base)

::NOTICE::

You must have an even number of Hydrogen atoms in order to subtract H₂O

HClO₃ -> 2[HClO₃] -> H₂Cl₂O₆

                                  -H₂     O

                                   ---------

                                       Cl₂O₅

Thus: Cl₂O₅ + H₂O <-> 2HClO₃

SALTS

Binary Salts

“+” ion – stem – ide

NaCl -> Sodium Chloride

KF -> Potassium Fluoride

Li₂S -> Lithium Sulfide

Ca₂N₃ -> Calcium Nitride

Cu₂Se -> Copper I Selenide

(NH₄)₃P -> Ammonium Phosphide

Ternary

Positive Ion + Negative Polyatomic Ion

Metal+stem-ate

NaClO₃ -> Sodium Chlorate

Mg(NO₃)₂ -> Magnessium Nitrate

CuSO₄ -> Copper II Sulfate

Polyatomic with 1 less Oxygen Atom

Metal+Stem-ite

NaClO₂ -> Sodium Chlorite

Mg(NO₂)₂ -> Magnessium Nitrite

CuSO₃ -> Copper II Sulfite

Polyatomic with 2 less Oxygen Atoms

Metal+Stem-ite

NaClO -> Sodium Hypochlorite

Mg(NO)₂ -> Magnessium Hyponitrite

CuSO₂ -> Copper II Hyposulfite

Polyatomic with 1 more Oxygen Atom

Metal+Per-Stem-ate

NaClO₄ -> Sodium Perchlorate

Mg(NO₄)₂ -> Magnessium Pernitrate

CuSO₅ -> Copper II Persulfate

(REMEMBER: when adding or subtracting Oxygen from a Polyatomic Ion, the Charge of that Ion remains the same: (ClO₃)^-1 (ClO₄)^-1 )

(REMEMBER: When in doubt of the formula of a given polyatomic ion, refer to other elements in the same family. Elements of the same family have similar reactivity: ClO₃-> Chlorate, FO₃-> Fluorate, BrO₃ -> Bromate)

***Arsenic reacts similar to Phosphorus, not Nitrogen***

    NO₃, PO₄ , AsO_? Because Arsenic is in closer proximity to Phosphorus on the periodic table, it will react more like Phosphorus than Nitrogen, thus:

Arsenate -> AsO₄