Stock System-New Naming System

• Some metal elements can form two or more cations with a different charge. The stock system denotes the specific ion by putting the charge in ( ).

• Example:• Iron (II) has a + 2 charge• Iron (III) has a +3 charge

Other common examples

• Lead (II) has a +2 charge• Lead (IV) has a +4 charge• Tin (II) has a + 2 charge• Tin (IV) has a +4 charge• Copper (I) has a +1

charge• Copper (II) has a +2

charge

Old Nomenclature-Don’t have to memorize these• Copper (I) – cuprous• Copper (II) – cupric• Iron (II) – ferrous• Iron (III) – ferric• Tin (II) – stannous• Tin (IV) – stannic• Lead (II) – plumbous• Lead (IV) – plumbic

Naming ionic compounds

• Nomenclature-naming system– Positive ions is first, then negative ion– Ex: sodium chloride NaCl

Practice• Write formulas for the following:• Copper (II) Sulfate

– CuSO4

• Iron (III) oxide– Fe2O3

• Zinc (II) sulfide – ZnS

• Vandium (IV) chloride– VCl4

• Cobalt (III) Nitrite– Co(NO3)3

Practice

• http://www.quia.com/jg/65800.html -

Compounds containing Polyatomic ions

• Treat the polyatomic ion as a single atom• Always put polyatomic ion in parentheses

if there is more than 1 of them• Example: ammonium chloride

– NH4Cl

Practice• Barium Nitrate

– Ba(NO3)2

• FeSO4

– iron (II) sulfate

Naming Molecular Compounds• Old way of naming Molecular Compounds

requires the Use of prefixes. (memorize These)

1 = mono2 = di3 = tri4 = tetra5 = penta6 = hexa7 = hepta8 = octa9 = nona10 = deca

• Naming Binary Molecular Compounds:• Compounds with 2 elements

– The least EN Atom goes first• C,P,N,H,S,I,Br,Cl,O,F

– The element is given a prefix if it contributes more than one element to the molecule.

– The second element: Combine a prefix with the root of that element with -ide at the end.

• Dioxide, pentoxide• This is true for most molecules containing 2

elements

– The o or a at the end of a prefix is usually dropped when the name of the element begins with a vowel

Practice1. CO

– Carbon Monoxide2. CO2

– Carbon Dioxide3. CCl4

– Carbon TetraChloride4. SiF4-

– Silicon Tetraflouride5. Nitrogen Monoxide

– NO6. N2O3

– Dinitrogen Trioxide7. Phosphorus Trichloride

– PCl3

Acids• Oxyacid-Acids that contain hydrogen,

Oxygen and another atom (usually a non-metal)

– H3PO4: Phosphoric Acid

– HNO2: Nitrous Acid

– Usually made from polyatomic ions and the addition of enough Hydrogens to balance out the ion.

Acids Naming: • Decide which polyatomic Ion is being used and

use that rootword• Polyatomic ions that end in

– ate ic– ite ous

• Rootword(ic or ous) and Add Acid

Practice

• HNO2

– Nitrous Acid

• Sulfuric Acid– H2SO4

Acids• Binary Acids-Acids that consist of 2

elements: usually Hydrogen and one of the Halogens (there are others)

– HCl: Hydrochloric Acid– HF: Hydroflouric Acid

Naming:• Hydro goes first• Add the name of the second atom with

ic at the end

• H2S– Hydrosulfuric Acid

• Hydrobromic Acid– HBr

Acids-Practice

• HI– Hydroiodic Acid

• CH3COOH– Acetic Acid

• Sufurous Acid– H2SO3

• Carbonic Acid

• H2CO3

Using Chemical Formulas• Subscript indicates how many moles of that

atom or polyatomic ion are in 1 mole of that compound.

• KNO3

• Na2SO4

• Ca(OH)2

• (NH4)2SO3

Using Chemical Formulas• Formula mass-sum of all the average

atomic masses of all elements in compound.

• Ex: H2SO4

• 2 Hydrogen 2 x 1.01 = 2.02• 1 Sulfur 1 x 32.07 =32.07• 4 Oxygen 4 x 16.00 =64.00

total = 98.09

OR• EX: NaCl

• 1 sodium ion 22.99• 1 Chloride ion 35.45

total= 58.44

Practice

• (NH4)3(PO4)

• Al2O3

• Na2O

Molar Mass as a Conversion Factor

• Converting between moles and grams with compounds.– 1st calculate formula mass of given

compound. (unit gram/mole)– 2nd convert either by multiplying or

dividing by the formula mass

• molesgrams (x) by formula mass• Gramsmoles (divide) formula

mass

Practice• What is the mass of 4.5 moles

of Ca(CO3)?– 4.5 x 102 g Ca(CO3)

• What is the mass of 2.0 moles of Na(NO3)?– 1.7 x 102 g Na(NO3)

• How many moles are contained in 25.0 grams of AgCl?– .174 mol AgCl

• How many moles are contained in 5.0 grams of ZnCl2?– .037 mol ZnCl2

Percent Composition• Gives the percent by molar mass of each

element in a compound.• 1st calculate the total molar mass of the

compound• H2SO4

2 H x 1.01 = 2.021 S x 32.07 = 32.074 O x 16.00 = 64.00

98.09

continued• 2nd Divide each individual atoms mass

by the total mass. • 3rd Multiply each by 100 (or move

decimal two places to the right)2 H x 1.01 = 2.01/98.16 = 0.0205

=2.05%

1 S x 32.07 = 32.07/98.16 = 0.327 =32.7%

4 O x 16.00 = 64.00/98.16 = 0.652 =65.2%

Check to make sure % adds to 100

(or close to 100)

• More Practice Pg 244 Practice Problems

• ZnSO4•7H2O– 42.85%

Determining Chemical Formulas• Empirical formula-symbols of elements

in compound showing the smallest whole number ratio.

• Convert percents of elements in a compound into formula.

How to:

• 1st change % to grams• 2nd convert grams to moles• 3rd divide each by the least• Ex: Determine the formula

of a compound made up of the following percents: 32.38 % Na

22.65 % S 44.99 % O

Practice problems 1-3 p.247

Molecular formulas

• Actual formula of a molecular compound

• C2H4 simplifies to CH2

• C3H6 simplifies to CH2

• C2H4 (ethene) and C3H6 (cyclopropane)

How the empirical formula relates to the molecular formula:• EF = empirical formula• MF = molecular formula• X( EF) = (MF)• 1st solve for x• X= (MF)/(EF) • HINT-BIG NUMBER

ALWAYS GOES ON TOP• Multiply (EF) by x to get

the molecular formula

Example

• The empirical formula of a cpd of phosphorus and oxygen was found to be P2O5. the molar mass of this cpd is 283.89g/mol. What is the cpd’s molecular formula?

Practice Problems 1-2 p. 249

Give the formula for the following:• 1. potassium oxide• 2. lithium phosphide• 3. aluminum chloride• 4. calcium bromide• 5. iron(II)oxide• 6. iron(III)oxide• 7. tin(IV)fluoride• 8. copper(II)chloride• 9. lead (II) sulfide• 10. magnesium chloride

Determine the molecular formula:• 1. Emperical formual =

CH, molar mass = 78 g/mole

• 2. Emperical formula = NO2, molar mass = 92.02 g/mol

• 3. Mesitylene has an empirical formula of C3H4. What is the molecular formula(mass 121)?