1. Chemical Formulas and Chemical Compounds Chapter 7

2. Chemical Formulas Aluminum Sulfate formula unit Al 2 (SO 4 ) 3 Carbon Tetrachloride molecule CCl 4

3. Monatomic Ions Def: ions formed from a single atom Naming ions Cation – use element name Li +1 – Lithium ionAl +3 – Aluminum ion Anion – change ending of element to –ide N -3 – Nitride ionO -2 – Oxide ion

4. Monatomic Ions d – block elements and others with multiple ions Use Roman numeral in name Fe +3  Iron(III) ion Fe +2  Iron(II) ion Metals always have positive charge

6. Polyatomic Ions

7. NO 3 -  Nitrate NO 2 -  Nitrite The –ate means 1 more oxygen SO 4 -2  Sulfate SO 3 -2  Sulfite

8. Polyatomic Ions ClO 4 -  Perchlorate ClO 3 -  Chlorate ClO 2 -  Chlorite ClO -  Hypochlorite

9. Binary Ionic Compounds Def: composed of 2 elements Total (+) charge must = total (-) charge Write the formula: Mg and Cl Mg +2 Cl -1 MgCl 2 K and N Al and O

10. Compounds with Polyatomic Ions Iron(II) and Nitrite Silver and Chromate Calcium and Hydroxide

11. Naming Ionic Compounds Name the cation first, then the anion NaOH RbCl Ag 2 SO 3 Fe 3 N 2 CuMnO 4

12. Writing Formulas Potassium sulfide Copper(II) sulfate Sodium carbonate Calcium chloride Aluminum hypochlorite

13. Naming Binary Covalent Compounds CO, CO 2 We use PREFIXES in the name!! Only COVALENT compounds use PREFIXES

14. Prefixes Mono-OneHexa-Six Di-TwoHepta-Seven Tri-ThreeOcta-Eight Tetra-FourNona-Nine Penta-FiveDeca-Ten

15. Covalent Naming Rules 1.Use prefixes to show how many of each element Single atom in first element, mono is not used 2.The second element name ends in – ide 3.Drop vowel at end of prefix if element begins with vowel (except: di and tri)

16. Examples N 2 O 4 PCl 5 S 3 Br 6 Nitrogen Dioxide Boron Trifluoride Diphosphorus Pentoxide

17. Naming Acids Begin with Hydrogen (H) 2 types of acids: 1. Oxyacids: hydrogen and polyatomic ion 2. Binary Acids: w/o oxygen hydrogen and halogen **CN -

18. Naming Oxyacids Replace ending of anion name Anion SuffixAcid Suffix - ite- ous - ate- ic

19. Naming Oxyacids H 2 SO 4  anion SO 4 -2  Sulfuric Acid H 2 SO 3 HClO 4 HNO 3

20. Naming Oxyacids Acetic Acid Dichromic Acid Nitrous Acid

21. Naming Binary Acids Use prefix hydro- Use suffix –ic Followed by acid

22. Naming Binary Acids HCl HF HI HBr HCN

23. Formula Mass Mass of H 2 O? Formula Mass: mass of molecule, formula unit, or ion is sum of masses of all atoms represented (amu) Ca(NO 3 ) 2

24. Molar Mass Def: mass of 1 mole of compound – use molar masses of elements (g/mol) (NH 4 ) 2 CrO 4

25. Molar Mass in Conversions Remember flow chart?? Grams  Moles  Particles What is mass (g) of 3.04 mol of ammonia vapor, NH 3 ? How many molecules are in 4.15 x 10 -5 g C 6 H 12 O 6 ?

26. More Conversions How many H atoms are in 7.1 moles of C 6 H 12 O 6 ? How many formula units are in 4.5 kg Ca(OH) 2 ? What is the mass of H 2 SO 4, if you have 1.53 x 10 23 hydrogen ions in your compound?

27. Percent Composition A basket of fruit = 120 g 3 apples = 50 g 2 oranges = 35 g 2 bananas = 20 g Basket = 15 g What percentage of the basket’s mass is from the apples?

28. Percent Composition What is the percent composition by mass of each element in (NH 4 ) 2 O? What percentage by mass of Al 2 (SO 4 ) 3  6H 2 O is water?

29. Empirical Formula Def: formula showing smallest whole- number mole ratio Ex: B 2 H 6  Molecular Formula BH 3  Empirical Formula

30. Finding Empirical Formula Determine the empirical formula of the compound with 17.15% C, 1.44% H, and 81.41% F. CHF 3

31. Finding Empirical Formula Find empirical formula of 26.56% K, 35.41% Cr, and rest O. K 2 Cr 2 O 7

32. Finding Molecular Formula x(empirical formula) = molecular formula x(Emp.Form Mass) = Molec.Form Mass x = Molecular Mass Empirical Mass

33. Finding Molecular Formula Determine molecular formula of compound with empirical formula CH and formula mass of 78.110 amu.

34. Finding Molecular Formula Sample has formula mass of 34.00 amu has 0.44g H and 6.92g O. Find its molecular formula.