Practice exam 2
1) Differentiate between the following terms:
a. Species reduced vs. reducing agent
b. Species oxidized vs. oxidizing agent
c. Oxidation state vs. actual charge
2) If 10.g of AgNO3 is available, what volume of 0.25M AgNO3 solution can be prepared?
3) Calculate the sodium ion concentration when 70.0mL of 3.0M sodium carbonate is added to 30.0mL of
1.0M sodium bicarbonate.
4) Soluble? Or insoluble?
Zinc chloride, lead(II) nitrate, lead(II) sulfate, sodium iodide, cobalt (III) sulfide, chromium (III) hydroxide,
magnesium carbonate, ammonium carbonate
5) Is there a precipitate when the following are mixed? If there is, what is it?
Hg2(NO3)2(aq) + CuSO4(aq)
Write the balanced formula equation, complete ionic equation, and net ionic equation. If no precipitate,
write no reaction.
6) What mass of barium sulfate can be produced when 100.0mL of a 0.100M solution of barium chloride is
mixed with 100.0mL of a 0.100M solution of iron (III) sulfate? Calculate the concentrations of each ion
remaining in solution after precipitation is complete.
7) 2.00L of a 2.00M aqueous solution of copper(II) nitrate is mixed with 2.00L of a 3.00M aqueous solution of
potassium hydroxide. Determine the concentrateions of all ions left in product solution and the mass of
the solid formed.
8) You have two 500.0mL aqueous solutions. Solution A is a solution of silver nitrate, and solution B is a
solution of potassium chromate. The masses of the solutes in each of the solutions are the same. When
the solutions are added together, a blood-red precipitate forms. After the reaction has gone to
completion, you dry the solid and find that it has a mass of 331.8g
a. Calculate the concentration of the potassium ions in the original potassium chromate solution
b. Calculate the concentration of the chromate ions in the final solution
9) Write the balanced formula equation, complete ionic equation, and net ionic equation for the acid-base
reaction: aqueous strontium hydroxide mixed with hydroiodic acid.
10) What volume of 0.0500M Ba(OH)2 will react completely with 25.00mL of 0.200M HCl?
11) A 25.00mL sample of hydrochloric acid solution requires 24.16mL of 0.106M sodium hydroxide for
complete neutralization. What is the concentration of the original hydrochloric acid solution?
12) The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate
a sample of potassium hydrogen phthalate (KHP). KHP is an acid with one acidic hydrogen and a molar
mass of 204.22g?mol. In the titration, 34.67mL of the sodium hydroxide solution was required to react
with 0.1082g KHP. Calculate the molarity of sodium hydroxide.
13) Specify which species is oxidizing agent and which is reducing agent, also which species is being reduced
and which is being oxidized. Then balance the redox reaction that is in acidic solution, using the half
reaction method.
a. H3AsO4(aq) + Zn(s)
AsH3(g) +MnO2(s)
b. Cr(NCS)64- (aq)+ Ce4+(aq)
Cr3+(aq) + Ce3+(aq) + NO3-(aq) +CO2(g) + SO42-(aq)
and these base reactions:
c. CN-(aq) + MnO4- (aq)
CNO- (aq) + MnO2(s)
44+
d. Fe(CN)6 (aq) + Ce (aq)
Ce(OH)3(s) + Fe(OH)3 (s) + CO32-(aq) + NO3-(aq)
14) Carminic acid, a naturally occurring red pigment extracted from the cochineal insect, contains only
carbon, hydrogen, and oxygen. It was commonly used as a dye in the first half of the 19th century. It is
53.66%C and 4.09% H by mass. A titration required 18.02mL of 0.0406M NaOH to neutralize 0.3602g
carminic acid. Assuming that there is only one acidic hydrogen per molecule, what is the molecular
formula of carminic acid?
15) A gauge on a compressed gas cylinder reads 2200psi (pounds per square inch; 1atm = 14.7psi). Express
this pressure in each of the following units.
a. Standard atmospheres
b. Megapascals (MPa)
c. Torr
16) A balloon is filled to a volume of 7.00x102mL at a temperature of 20.00C. The balloon is then cooled at
constant pressure to a temperature of 1.00x102K. What is the final volume of the balloon?
17) A flask that can withstand an internal pressure of 2500 torr, but no more, is filled with a gas at 21.0 0C and
758 torr and heated. At what temperature will it burst?
18) Concentrated hydrogen peroxide solutions are explosively decomposed by traces of transition metal ions
(such as Mn or Fe):
2H2O2(aq)
2H2O(l) + O2(g)
What volume of pure O2(g) , collected at 270C and 746 torr, would be generated by decomposition of 125g
of a 50.0% by mass hydrogen peroxide solution? Ignore any water vapor that may be present.
19) Given that a sample of air is made up of nitrogen, oxygen, and argon in the mole fractions 78% N 2, 21%O2,
and 1.0% Ar, what is the density of air at standard temperature and pressure?
20) A mixture of 1.00gH2 and 1.00g He is placed in a 1.00L container at 270C. Calculate the partial pressure of
each gas and the total pressure.
21) A steel cylinder contains 5.00 mol of graphite (pure carbon) and 5.00 mol of O2. The mixture is ignited and
all the graphite reacts. Combustion produces a mixture of CO gas and CO2 gas. After the cylinder has
cooled to its original temperature, it is found that the pressure of the cylinder has increased by 17.0%.
Calculate the mole fractions of CO, CO2, and O2 in the final gaseous mixture.