Homework Set 2
Pre AP Chemistry: Chemical Quantities
Due: Beginning of Class Monday March 12
Provide the answers to the following questions. Show all of your work with correct units throughout your
calculations and final answers. Box or circle your final answer.
1. Convert 453. kilograms to ounces. (Hint: 1 lb = 454g),
2. Convert 3.800 moles of tropylium to ions of tropylium.
3. Convert 35.4 micrograms (
) of iron(III) sulfide to moles of iron(III) sulfide.
4. Provide the molar mass of H2O.
5. For a 63.7 g sample of Mn(S2O3)4, determine the grams of sulfur in the sample?
6. A compound is formed when 9.03 g of Mg is combined with 3.48 g N. Determine the percent
composition of Mg and N in this compound.
7. When a 14.2 g sample of mercury(II) oxide is decomposed into its elements, 13.2g of Hg is obtained.
Determine the percent composition of the mercury(II) oxide.
8. Calculate the percent composition (by mass) of carbon, hydrogen, and oxygen in C 12H22O11.
9. Determine the empirical formula (CaHbNcOd) for the following data: 62.1% C, 5.21% H, 12.1% N.
10. Ibuprofen, a headache remedy, contains 75.69% C, 8.80% H, and 15.51% O by mass. Determine the
empirical AND molecular formula (CaHbOc) if ibuprofen has a molar mass of 206. g/mol.
11. Caffeine, a stimulant, found in coffee, contains 49.5% C, 5.15% H, 28.9 % N, and 16.5% O by mass.
Determine the empirical AND molecular formula (CaHbNcOd) if caffeine has a molar mass of 195.
g/mol.
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