Chemistry Test Review
Naming Compounds, Writing Formulas, Molar Mass, Percent Composition,
Empirical and Molecular Formulas
1. Be able to recognize and name ionic compounds (metal + non-metal), including those with Roman
Numerals. You will also have to write the formula when given the compound name.
 Roman Numerals indicate charge on transition metal, not its subscript. They range from
1+ - 6+, except for Ag 1+, Zn2+, and Cd2+. Charges will add up to Zero.
 Watch for polyatomic ionic compounds. Hint – a metal followed by 2 or more non-metals.
You may use the green sheet.
 Name the metal first, then the non-metal ending in –ide – except polyatomic compounds
which use the name of the compound as shown on green sheet
2. Be able to recognize and name covalent compounds (non-metals). You will also have to write
formulas for these as well.
 The subscript on each element becomes its prefix when naming. Mono is only used for
second element. Drop the “a” when applying a prefix to oxygen. Second element ends in
–ide. Know your prefixes (bi-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nono-, deca-)
 The prefix becomes the subscript when writing formula from the name
3. Know about the concept and calculations related to the counting unit of a mole developed by
Avogadro. 6.022 x 1023 is the number of atoms or molecules in a mole. For gases, 22.4 L of gas =
1 mole
4. Know how to calculate molar mass.
 For a single element it is the atomic mass on periodic table
 For a molecule or compound, you add the molar mass of each separate element
5. Know how to calculate percent composition as amount of specific element x 100%
Total mass of compound
6. Know how to determine empirical formulas and empirical formula mass for ionic compounds
 Find no. of moles of each element. Divide by smallest no. of moles to get to lowest whole
number ratio (these tell you the subscripts on each element)
7. Know how to determine molecular formulas and molecular/formula mass for covalent compounds
 Experimental actual molecular/formula mass = ratio to apply to subscripts of all elements
Empirical formula mass
in compound
You may use your periodic table, polyatomic ion sheet, and a calculator. YOU MAY NOT USE THIS
REVIEW. Completed review worth up to 5 points on test grade.
Practice problems follow
Write the name of the following ionic compounds:
1. SrF2
2. Na2O
Write the chemical formula for the following ionic compounds:
3. Cesium nitride
4. Indium fluoride
Write the name the of the following metal + polyatomic ion compound
5 . Be3(PO4)2
6. LiC2H3O2
Write the chemical formula for the following metal + polyatomic ion compounds
7. rubidium dichromate
8 barium bicarbonate
Write the name for the following varying charges metals (Use parentheses and Roman Numerals)
9
FeCl2
10. HgO
Write the formula for the following metals with varying charges
11. Lead (II) chloride
12. Chromium (III) acetate
Write the name for the following covalent compounds
13. PCl3
14. N2S3
Write the formula for the following covalent compounds
15.
Pentaboron trinitride
16
Selenium difluoride
17. Determine the number of atoms in 0.75 moles of copper
18. How many moles are there in 5.25 x 1024 atoms?
19. Determine the number of moles of magnesium in 18.85 grams of material
20. Determine the number of molecules of potassium chloride in 35 grams of the compound
21. How many moles are in 50 L of carbon dioxide?
22. What is the molar mass of LiCl?
23. What is the molar mass of iron(II) permanganate?
Determine the percent composition for each element in the following:
24. NH4C2H3O2
25. Calcium carbonate
Empirical and Molecular Formulas
26. Rubbing alcohol was found to contain 60.0 % carbon, 13.4 % hydrogen, and the remaining mass was
due to oxygen. What is the empirical formula of rubbing alcohol?
27. A well-known reagent in analytical chemistry, dimethylglyoxime, has the empirical formula C2H4NO.
Experimentation has determined its actual molar mass is 116.1 g/mol, what is the molecular formula of
the compound?
28. A compound is 2.46%H, 39.1%S, and 58.5%O. What is its empirical formula? What would be the
empirical mass?