Naming Chemical Compounds Nomenclature-naming system

Naming Ionic Compounds Positive ions are first, then negative ions –Ex: sodium chloride NaCl The metal keeps it’s name The nonmetal gets a suffix of –ide –MgCl 2 –K3P–K3P –Al 2 O 3 –BeS

Stock SystemNaming 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 ( ). Examples: –Iron (II) has a + 2 charge –Iron (III) has a +3 charge

Possible Charges Roman Numeral –I–I –II –III –IV –V–V –VI –VII Charge –+1 –+2 –+3 –+4 –+5 –+6 –+7

Practice Write Names for the following: CuSO 4 –Copper (II) Sulfate Fe 2 O 3 –Iron (III) oxide ZnS –Zinc (II) sulfide VCl 4 –Vandium (IV) chloride Co(NO 3 ) 3 –Cobalt (III) Nitrite MnSO 4 –Manganese (II) Sulfate

Practice a)Radium chloride b)chromium(II)chloride c)Aluminum phosphate d)copper(I)sulfate e)Magnesium sulfate f)nitric acid g)Sodium oxide -

Compounds containing Polyatomic ions Always put polyatomic ion in parentheses if there are more than 1 of them Example: ammonium chloride –NH 4 Cl Practice Barium Nitrate –Ba(NO 3 ) 2 FeSO 4 –iron (II) sulfate

Naming Molecular Compounds Use prefixes when naming simple molecular compounds (memorize these) 1 = mono 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa 7 = hepta 8 = octa 9 = nona 10 = 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 first 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

Practice 1.CO –Carbon Monoxide 2.CO 2 –Carbon Dioxide 3.CCl 4 –Carbon TetraChloride 4.SiF 4 - –Silicon Tetraflouride 5.Nitrogen Monoxide –NO 6.N 2 O 3 –Dinitrogen Trioxide 7.Phosphorus Trichloride –PCl 3

Using Chemical Formulas Subscript indicates how many moles of that atom or polyatomic ion are in 1 mole of that compound. KNO 3 Na 2 SO 4 Ca(OH) 2 (NH 4 ) 2 SO 3

Using Chemical Formulas Formula mass -sum of all the average atomic masses of all elements in compound. Ex: H 2 SO 4 2 Hydrogen 2 x 1.01 = Sulfur 1 x = Oxygen 4 x =64.00 total = OR EX: NaCl 1 sodium ion Chloride ion to tal= 58.44

Practice (NH 4 ) 3 (PO 4 ) Al 2 O 3 Na 2 O

Molar Mass as a Conversion Factor Converting between moles and grams with compounds. –1 st calculate formula mass of given compound. (unit gram/mole) –2 nd convert either by multiplying or dividing by the formula mass moles  grams (x) by formula mass Grams  moles (divide) formula mass

Practice What is the mass of 4.5 moles of Ca(CO 3 )? –4.5 x 10 2 g Ca(CO 3 ) What is the mass of 2.0 moles of Na(NO 3 )? –1.7 x 10 2 g Na(NO 3 ) How many moles are contained in 25.0 grams of AgCl? –.174 mol AgCl How many moles are contained in 5.0 grams of ZnCl 2 ? –.037 mol ZnCl 2

Percent Composition Gives the percent by molar mass of each element in a compound. 1 st calculate the total molar mass of the compound H 2 SO 4 2 H x 1.01 = S x = O x =

continued 2 nd Divide each individual atoms mass by the total mass. 3 rd Multiply each by 100 (or move decimal two places to the right) 2 H x 1.01 = 2.01/98.16 = =2.05% 1 S x = 32.07/98.16 = =32.7% 4 O x = 64.00/98.16 = =65.2% Check to make sure % adds to 100 (or close to 100) More Practice Pg 244 Practice Problems ZnSO 4 7H 2 O –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: 1 st change % to grams 2 nd convert grams to moles 3 rd divide each by the least Ex: Determine the formula of a compound made up of the following percents: % Na % S % O

Practice problems 1-3 p.247

Molecular formulas Actual formula of a molecular compound C 2 H 4 simplifies to CH 2 C 3 H 6 simplifies to CH 2 C 2 H 4 (ethene) and C 3 H 6 (cyclopropane)

How the empirical formula relates to the molecular formula: EF = empirical formula MF = molecular formula X( EF) = (MF) 1 st 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 P 2 O 5. the molar mass of this cpd is g/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 = NO 2, molar mass = g/mol 3. Mesitylene has an empirical formula of C 3 H 4. What is the molecular formula(mass 121)?