CHM2045 Exam 1 Review Questions
Fall 2015
1) Which of the chemical formulas are written correctly?
a. Magnesium Dichloride MgCl2
b. Phosphorus Pentafluoride PF5
c. Sodium Chloride NaCl2
d. Potassium Bromide KBr
e. Monocarbon Monoxide CO
f. Dinitrogen Trioxide N2O3
2) Which of the following is false?
a) Iron(III) sulfide has three Fe atoms
b) HCl is a strong acid
c) Z is the atomic number symbol
d) NO3 is nitrogen trioxide
3) Which of the following is closest to the mass of chromium in 1.064 g Cr2O3?
a) 0.342 g
b) 0.727 g
c) 0.682 g
d) 1.064 g
4) Compound X contains the following elemental mass percent: 54.51% C, 9.156% H, and 36.33% O.
The molecular weight is 88.07 g/mol. Which choice is a possible molecular formula for compound X?
Bonus: What is the Empirical Formula?
a) C2H4O
b) C3H5OH
c) C3H7COOH
d) C3H7CHO
5) A 1.013-g sample of ZnSO4•xH2O is dissolved in an aqueous solution of BaCl2. The pure BaSO4
precipitate is filtered out of solution, dried, and its mass is determined to be 0.8223 g. What is the
value of x in ZnSO4•xH2O?
CHM2045 Exam 1 Review Questions
Fall 2015
6)
How many grams of sodium hydroxide are needed to make 250 mL of a 0.200 M NaOH?
7) Balance the following equation:
FeBr3 + H2SO4 −−→ Fe2 (SO4 ) 3 + HBr
8) Please find the oxidation numbers for each element of the following reaction (rxn)
Fe2O3 + 3CO → 2Fe + 3CO2
9) Which of the following are redox rxns?
a) Na+ (aq) + Cl- (aq) → NaCl (aq)
b) KNO3 (s) → 2 K2O(s) + 2 N2(g) + 5 O2(g)
c) CH4 + 2O2 → CO2 + 2H2O
CHM2045 Exam 1 Review Questions
Fall 2015
10) Given the reaction: 3 H2S + 2 FeCl3 = Fe2S3 + 6 HCl
We have 60.0 g of FeCl3 reacts with 42.0 g of H2S. Which is the limiting reactant. Also, what is
the mass of HCl produced and what is the percent yield?
11) Name or write the acids correctly
a) HCl
b) Hydro Iodic Acid
c) HC2H3O2
d) Chlorous Acid
e) HBr
f) H2SO4
12) Name or write the bases correctly
a) NaOH
b) KOH
c) NH3
d) Ca(OH)2
13) How many sodium atoms are contained in 1.00mL of 0.184 M aqueous sodium sulfite?
CHM2045 Exam 1 Review Questions
Fall 2015
14) In which of the following equations is the acid (proposed acid is underlined) incorrectly
labeled?
HCl + H2O → Cl- + H3O+
H2PO4- + H2O → H3PO4 + OHCN- + H2O → HCN + OHCH3COOH + H2O → CH3COO- + H3O+
HCO3- + H2O → H2CO3 + OH-
15) If volumes are additive and 100.0 mL of 0.60 M sodium chloride is mixed with 120 mL of a calcium
chloride solution to give a new solution in which [Cl-1] is 0.34 M, what is the concentration of the
calcium chloride used to make the new solution?
16) A scientist added 70.0 mL of a sodium hydroxide solution to 200.0 mL of 0.400 M HCl. The resulting
solution was then treated with an excess of aqueous chromium (III) nitrate, resulting in the
formation of 3.06 g of precipitate. Determine the concentration of the initial sodium hydroxide
solution.
CHM2045 Exam 1 Review Questions
Fall 2015
17) Aqueous potassium iodide reacts with aqueous copper(II) nitrate to form a mixture of solid
copper(I) iodide, solid iodine, and aqueous potassium nitrate. What volume of a 0.2089 M solution
of aqueous potassium iodide will contain enough potassium iodide to react exactly with the
copper(II) nitrate in 43.88 mL of a 0.3842 M solution of aqueous copper(II) nitrate?
18) Describe the following terms
a) Polyatomic Ion
b) Molarity
c) Acid
d) Base
e) Redox Reaction
f)
Combustion Reaction
g) Precipitation Reaction
h) Acid-base Reaction
CHM2045 Exam 1 Review Questions
Fall 2015
19) Select the false statement below
(a) Pb2+(aq) + 2I−(aq) → PbI2(s) is a precipitation reaction but is not a redox reaction
(b) CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) is a combustion reaction and a redox reaction
(c) Ca(s) + F2(g) → CaF2(s) is a precipitation reaction and a redox reaction
(d) HNO3(aq) + KOH(aq) → H2O(l) + KNO3(aq) is an acid-base reaction but is not a redox reaction
(e) H2SO4(aq) + Ba(OH)2(aq) → 2H2O(l) + BaSO4(s) is a precipitation reaction and an acid-base
reaction
20) Sweetener saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten (10) tablets with a total
mass of 0.5894 g were dissolved in water. They were oxidized to convert all the sulfur to sulfate ion,
which was precipitated by adding an excess of barium chloride solution. The mass of barium sulfate
obtained was 0.5032 g. What is the average mass percent of saccharin in the tablets?
CHM2045 Exam 1 Review Questions
Fall 2015
GOOD LUCK ON THE EXAM AND GET A GOOD NIGHT SLEEP
THE NIGHT BEFORE TEST! 
-Broward Teaching Center