Name ____________________________________ Date ___________________ Pr. ___________
Review for Ch. 7 Test
7.1 Chemical Names & Formulas
- Know how to name ionic compounds, covalent compounds, compounds with transition metals, acids, and
hydrates.
- Know how to use the criss-cross method to write the formulas for all of the above.
- You are expected to know all polyatomic ions and naming prefixes (1 – 10).
Name the examples:
Write the formulas:
1. CCl4
11. Sulfurous acid
2. CuSO4
12. Sodium oxide
3. PbI4
13. Ammonium chromate
4. CaO2
14. Iron (III) oxide
5. P4O10
15. Zinc sulfate heptahydrate
6. H2S
16. Mercury (I) dichromate
7. HNO3
17. Hydrobromic acid
8. HNO2
18. Trinitrogen heptoxide
9. Na2CO3 . 10H2O
19. Calcium hydroxide
10. As2O5
7.2 Oxidation Numbers
- Know how to assign oxidation numbers (remember: not always the same as charges) to elements of a
compound.
General Rules:
- Pure elements always have an oxidation number of _________.
- Fluorine always has an oxidation number of ________ .
- Oxygen will be a _______ or ______ , except in peroxide compounds. Then is it is a _____ .
- Hydrogen will be a ______ or ______ ( -1, if binary with a metal)
- Assign the ___________ electronegative element first, with the value it would have as an anion.
- Oxidation numbers should add up to ______ , if a neutral compound or add up to the charge if an
ion.
Try the following examples:
20. KClO3
22. BaO2
21. P4O10
23. NH4+
Name ____________________________________ Date ___________________ Pr. ___________
7.3 Using Chemical Formulas
- be able to calculate the molar mass (g/mol) aka formula mass (amu) of a compound, by using your periodic
table
- be able to convert moles to molecules/formula units using _________________ number =
?? Can you go from gram <-> molecules (in other words, 1st convert to mol, then to molecules)
- be able to calculate the percent composition of a compound, including hydrate compounds
Remember: ______________________ is the conversion factor between g to mol or mol to g
Try these problems:
24. Determine the molar mass of sodium bicarbonate.
25. Calculate the percent composition the anion.
26. How many molecules are present in 236 grams of sodium bicarbonate?
27. For those molecules of sodium bicarbonate, how many atoms are present?
Name ____________________________________ Date ___________________ Pr. ___________
7.4 Determining Chemical Formulas
- know the difference between an empirical formula and a molecular formula
- be able to determine an empirical formula
- knowing an empirical formula, be able to determine its molecular formula using molar masses.
28. A compound with the molar mass of 42.08 g/mol is found to be 85.64% carbon and 14.36% hydrogen
by mass. Determine its empirical formula.
29. Determine the molecular formula of this compound, using the information above.
General Tips:
1. Review all vocab & main concepts on Pg. 250. See your notes for more detail.
2. Use the review sheets to study and check your answers on my webpage. Go back over practice
problems, and try them again!
3. Don’t forget you’re calculator. And yes, significant figures matter.
Multiplication/ division: choose ____________________ sig figs
Addition/ subtraction: choose ______________ decimal places