This document provides a series of chemistry problems involving balancing equations, calculating formula weights, determining percentages of elements in compounds, relating the mole concept to Avogadro's number and molar mass, and performing stoichiometric calculations using moles, masses, and numbers of atoms/molecules. Students are asked to balance equations, calculate formula weights, determine percentages of elements in compounds, define key concepts like the mole and Avogadro's number, calculate molar masses and masses given moles or numbers of particles, and solve multi-step stoichiometry problems involving moles, masses, and numbers of atoms/molecules.

1. GENERAL CHEMISTRY-I (1411)
S.I. # 10
1. Balance the following equations:
a___ Li (s) + ___ N2 (g)  ___ Li3N (s)
b. ___ La2O3 (s) + ___ H2O (l)  ___ La(OH)3 (aq)
c. ___ NH4NO3 (s)  ___ N2 (g) + ___ O2 (g) + ___ H2O (g)
d. ___ Ca3P2 (s) + ___ H2O (l)  ___ Ca(OH)2 (aq) + ___ PH3 (g)
e. __ Ca(OH)2 (aq) + __ H3PO4 (aq) __ Ca3(PO4)2 (s) + __ H2O (l)
f. __ AgNO3 (aq) + __ Na2SO4 (aq)  __ Ag2SO4 (s) + __ NaNO3 (aq)
g. __ CH3NH2 (g) + _____O2 (g) _____CO2 (g) + _____H2O (g) + ____ N2 (g)
2. Determine the formula weights (FW) of each of the following:
a. Nitrous Oxide, N2O ____________ _____
b. benzoic acid, HC7H5O2 ____________ _____
c. Magnesium Hydroxide, Mg(OH)2 ____________ _____
d. Urea (NH2)2CO ____________ _____
e. isopentyl acetate CH3CO2C5H11 ____________ _____
3. Calculate the percent by mass of:
a. carbon in acetylene, C2H2
b. Hydrogen in ascorbic acid HC6H7O6
c. Hydrogen in ammonium sulfate (NH4)2SO4
d. Platinum in PtCl2(NH3)2
e. Oxygen in C18H24O2
f. carbon in C18H27NO3
4. a. What is Avogadro’s number, and how is it related to the mole? b. What is the
relationship between the formula weight of a substance and its molar mass?
5. a. what is the mass, in grams, of a mole of 12C? b. How many carbon atoms are

2. present in a mole of 12C?
6. a. What is the mass, in grams, of 0.0714 mol of iron(III) sulfate?
b. How many moles of ammonium ions are in 8.776 g of ammonium carbonate?
c. What is the mass, in grams, of 6.52x1021 molecules of aspirin, C9H8O4?
7. A sample of the male sex hormone testosterone, C19H28O2, contains 7.08x1020
atoms of hydrogen. a. How many atoms of carbon does it contain? b. How many
molecules of testosterone does it contain? c. How many moles of testosterone does it
contain? d. What is the mass of this sample in grams?