CHM 121_Final Review

Please DO NOT ASSUME these are the only types of problem which will be asked on your FINAL EXAM.

1.  Complete the table by filling the empty boxes

Symbol / 54
26 Fe 3+
Protons / 5 / 79
Neutrons / 6 / 16 / 117
Electrons / 5 / 18 / 79
Net charge / -3

2.  Fill in the blanks in the table

Cation / Anion / Formula / Name
SrCl2
Magnesium hydrogen carbonate
Co2+ / MnO4-
HIO

3.  Determine the empirical formula of the compound with the following composition: 20.2% Al and 79.8% Cl

4.  Determine the mass of CO2 and the mass of H2O produced by the combustion of 1.05 g of a compound with the empirical formula CH4O

5.  When heated, lithium reacts with nitrogen to form lithium nitride:

6Li(s) + N2(g) à 2 Li3N(s)

What is the theoretical yield of Li3N in grams when 12.3 g of Li is heated with 33.6 g of N2? If the actual yield of Li3N is 5.89g. What is the percent yield of the reaction? How much of excess reactant is left over from the reaction?

6.  Write a balanced molecular equation, ionic equation and net-ionic equation for the following reactions:

HClO4(aq) + Ba(OH)2(aq) à

7.  The concentration of Cu2+ ions in water (which also contains sulfate ions) discharged from a certain industrial plant is determined by adding excess sodium sulfide (Na2S) solution to 0.800 L of the water. The molecular equation is

Na2S(aq) + CuSO4(aq) à Na2SO4(aq) + CuS(s)

Write the net ionic equation and calculate the molar concentration of Cu2+ in the water sample if 0.0177 g of solid CuS is formed

8.  A piece of sodium metal reacts completely with water as follows:

2Na(s) + H2O(l) à 2NaOH(aq) + H2(g)

The hydrogen gas generated is collected over water at 25.0oC. The volume of the gas is 246 mL measured at 1.00 atm. Calculate the number grams of sodium used in the reaction. Vapor pressure of water at 25oC = 0.0313 atm

9.  Determine the partial pressure and the number moles of each gas in a 15.75 L vessel at 30.0oC containing a mixture of xenon and neon gases only. The total pressure in the vessel is 6.50 atm, the mole fraction of xenon is 0.761.

3