1. Chemical Quantities Notes I.Writing Formulas for Covalent Compounds-those containing 2 nonmetals. Prefix naming 1. _______6. _______ 2._______7. _______ 3._______8. _______ 4._______9. _______ 5._______10. _______

2. Practice: 1.nitrogen tetrasulfide _________ 2. carbon dioxide _________ 3. oxygen monofluoride _________ 4. sulfur hexachloride _________ 5. trioxygen decanitride _________

3. Writing Names for Covalent Compounds Use subscripts to determine the prefix Common Roots H: hydrC: carbN: nitrO: ox F: florSi: silicP: phosphS: sul Cl: chlorBr: bromI: iod

4. Practice: 6. CCl 4 _________________________ 7. NF 3 _______________________ 8. PBr 5 _________________________ 9. SF 6 _____________________________ 10. S 2 O 3 _________________________

5. Nomenclature – Ionic Compounds Composed of a metal and a nonmetal

6. Practice: 11. MgCl 2 ______________________________ 12. AlI 3 ______________________________ 13. Na 3 P ______________________________ 14. FeN ______________________________ 15. PbCl 2 ______________________________

7. 16. Na 3 PO 4 ______________________________ 17. Al 2 (SO 4 ) 3 ______________________________ 18. CuNO 3 ______________________________ 19. PbCO 3 ______________________________ 20. Li 2 SO 3 ______________________________

8. Rules for Writing Formulas for Ionic Compounds Write the symbol and charge for each ion. “Criss cross” the charges and remove the sign to get the subscripts. Subscripts are written after the ion and to the right.

9. Practice: 21. Magnesium phosphide_______________ 22. iron(II) bromide _______________ 23. Calcium oxide _______________ 24. sodium sulfide _______________ 25. Copper (II) iodide _______________

10. 26. aluminum sulfate _______________ 27. potassium chlorate _______________ 28.Copper (II) acetate _______________ 29.lead (II) nitrate _______________ 30. tin (II) nitrite _______________

11. Percent Composition – the percentage by mass of each element in a compound Percent composition = mass of the element X 100 Mass of the compound

12. Practice: Give the percent of each element of these compounds: 31. NaCl 32. H 2 O

13. 33. KMnO 4 34. CaSO 3

14. Part 3 – Empirical and Molecular Empirical Formulas An empirical formula is a “lowest common denominator” molecular formula for covalent molecules. It represents the ratio in which atoms (or MOLES of atoms) combine to form compounds, but not the actual numbers of atoms in the compound. Multiple compounds can have the same empirical formula.

15. Glucose, C 6 H 12 O 6, contains carbon, hydrogen, and oxygen. The ratio of carbon to hydrogen to oxygen is 1:2:1. CH 2 O is the empirical formula for glucose.

16. Review of changing grams to moles: 35. How many moles are in 18.0 grams of water? 36. How many moles are in 36.0 grams of water?

17. Practice: 37. Find the empirical formula of a compound with 58.5% Na and 35.5% Cl:

18. 38. Caffeine has the following percent composition: carbon, 49.48%; hydrogen 5.19%; oxygen, 16.48%; and nitrogen, 28.85%. What is its empirical formula?

19. 39. Find the empirical formula of a compound that contains 53.70% iron and 46.30% sulfur.

20. Molecular Formulas A molecular formula is a formula that represents the actual number of each atom in a compound. Whereas CH 2 O is the empirical formula for glucose, C 6 H 12 O 6­ is the molecular formula. An actual molecule of glucose contains six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. (Or six moles of carbon atoms, 12 moles of hydrogen atoms, and six moles of oxygen atoms).

21. Practice 40. Determine the molecular formula of a compound with an empirical formula of N 2 O and a molar mass of 176 grams per mole.

22. 41. A particular sugar is determined to have the following composition: 40.0% carbon, 6.7% hydrogen, and 53.5% oxygen. If the molar mass of the sugar is 180.0 g, find the molecular formula of the sugar.

23. 42. Ethene, a gas used extensively in preparing plastics and other polymers, has a composition of 85.7% carbon and 14.3% hydrogen. Its molar mass is 28 g. Find the molecular formula for ethane.