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Chemical Formulas Types of chemical formulas [X m Y n ] Molecular Actual # of atoms of each element Empirical Structural Relative # of atoms of each element Actual # of atoms and the bonds between them H 2 O 2 HO H-O-O-H 2
Models of Compounds 3
The distinction between mixtures and compounds. S 2- Fe 2+ A physical mixture of Fe and S 8 can be separated using a magnet. Fe and S have reacted chemically to form the compound FeS. The elements cannot be separated by physical means. 4
by: RBG 5
A. Naming Ionic Compounds Name: positive ion (cation), then negative ion (anion) Members of the same group = same ionic charge For anions, ion charge = group number minus 8 6
Common Monoatomic Ions 7
Practice Problem Name the ionic compound formed from the following pairs of elements: Magnesium and nitrogen Iodine and cadmium Strontium and fluorine Sulfur and cesium magnesium nitride cadmium iodide strontium fluoride cesium sulfide 8
Deriving Formulas A compound is neutral. Find the smallest number of each ion that will produce a neutral formula. magnesium nitride Mg 2+ and N 3- cadmium iodide Cd 2+ and I - strontium fluoride Sr 2+ and F - cesium sulfide Cs + and S 2- Mg 3 N 2 CdI 2 SrF 2 Cs 2 S 9
Metals with More Than One Monoatomic Ion 10
Practice Problem Fill up the following table: Formula Systematic Name Common Name SnCl 4 FeBr 3 CuBr Mn 2 O 3 tin(iv) chloride iron(iii) bromide copper(i) bromide manganese(iii) oxide stannic chloride ferric bromide cuprous bromide manganic oxide 11
Recall: Polyatomic Ions consists of two or more atoms covalently bonded together and has an overall charge. 12
Polyatomic Ions 13
Polyatomic Ions Oxyanions: formed when a nonmetal bonds with one or more oxygen atoms. 14
Naming Acids Binary acid: forms when certain gaseous compounds dissolve in water Prefix hydro- + anion nonmetal root + suffix -ic + acid hydro + chlor + ic + acid hydrochloric acid Oxoacid: similar with oxoanions, except: -ate in the anion becomes ic in the acid -ite in the anion becomes ous in the acid The prefixes hypo- and per- are retained. Thus, BrO 4 is perbromate, and HBrO 4 is perbromic acid; IO 2 is iodite, and HIO 2 is iodous acid. 15
Hydrated Ionic Compounds Hydrates: compounds with specific number of water molecules associated with each formula unit anhydrous copper(ii) sulfate CuSO 4 copper(ii) sulfate pentahydrate CuSO 4 5H 2 O 16
Numerical Prefixes for Hydrates 17
B. Naming Binary Covalent Compounds Recall: formed by 2 nonmetals Name the element with the lower group number first. Name the second element using the root with the suffix ide Use numerical prefixes to indicate # of atoms of each element 18
Numerical Prefixes for Hydrates and Binary Covalent Compounds 19
Practice Exercises SET 1 calcium and nitrogen potassium and carbonate sulfur and cesium sodium and fluorine tin(ii) and fluorine iron(iii) and oxygen SET 2 cobalt(i) and sulfur copper(ii) and nitrate potassium permanganate iron(iii) and chlorine calcium and oxygen carbon disulfide 20
Practice Exercises SET 3 LiCl HBr (g) HBr (aq) K 2 Cr 2 O 7 NH 4 NO 2 CaSO 4 SET 4 potassium hydrogen phosphate cesium carbonate sodium chromate calcium nitrate disulfur hexafluoride magnesium nitride 21
Practice Exercises SET 5 magnesium hydroxide dihydrogen monoxide tetrasulfur tetranitride calcium carbonate sodium bicarbonate calcium sulfate dihydrate SET 6 perchloric acid chloric acid chlorous acid hypochlorous acid nitrous acid sulfurous acid 22
Practice Exercises - Answers SET 1 calcium and nitrogen potassium and carbonate sulfur and cesium sodium and fluorine tin(ii) and fluorine iron(iii) and oxygen Ca 3 N 2 K 2 CO 3 Cs 2 S NaF SnF 2 Fe 2 O 3 23
Practice Exercises - Answers SET 2 cobalt(i) and sulfur copper(ii) and nitrate potassium permanganate iron(iii) and chlorine calcium and oxygen carbon disulfide Co 2 S Cu(NO 3 ) 2 KMnO 4 FeCl 3 CaO CS 2 24
Practice Exercises - Answers SET 3 LiCl HBr (g) HBr (aq) K 2 Cr 2 O 7 NH 4 NO 2 CaSO 4 lithium chloride hydrogen bromide hydrobromic acid potassium dichromate ammonium nitrite calcium sulfate 25
Practice Exercises - Answers SET 4 potassium hydrogen phosphate cesium carbonate sodium chromate calcium nitrate disulfur hexafluoride magnesium nitride K 2 HPO 4 Cs 2 CO 3 Na 2 CrO 4 Ca(NO 3 ) 2 S 2 F 6 Mg 3 N 2 26
Practice Exercises - Answers SET 5 magnesium hydroxide dihydrogen monoxide potassium cyanide calcium carbonate sodium bicarbonate calcium sulfate dihydrate Mg(OH) 2 H 2 O KCN CaCO 3 NaHCO 3 CaSO 4 2H 2 O 27
Practice Exercises - Answers SET 6 perchloric acid chloric acid chlorous acid hypochlorous acid nitrous acid sulfurous acid HClO 4 (aq) HClO 3 (aq) HClO 2 (aq) HClO(aq) HNO 2 (aq) H 2 SO 3 (aq) 28