These questions are meant to give you an idea of the test format and a chance to practice.
Most answers are provided for the multiple choice questions and some problems. They are
NOT the only source of questions and you should look at the Review Materials as well as the
assignments on Mastering Chemistry!
Characterizing Atoms by their subatomic particles
Indicate the number of protons, neutrons, and electrons in each of the following species:
a)
31P
15
b)
79Se
34
c)
51
V
23
d)
87Sr
38
Characterizing Ions
Give the number of protons and electrons in each of the following common ions:
a) Ca+2 #p+ =
#e- =
b) Ba2+ #p+ =
#e- =
3+
c) Al
#p+ =
#e- =
d) F
#p+ =
#e- =
f) N3#p+ =
#e- =
2+
g) Zn
#p+ =
#e- =
Formulas of Compounds
Write the formulas for the following ionic compounds:
a) silver iodide (containing the Ag+ ion)
b) manganese sulfide (containing Mn2+ ion)
c) mercury iodide (containing Hg2+ ion)
Writing Empirical formulas
What are the empirical formulas of the following compounds?
a) Al2F6
b) Li2C2O4
c) P2O5
d) FeCrO4
Naming compounds from formulas
Name these compounds:
a) AgCl
___________________________________
b) CaCO3
___________________________________
c) BaCl2
___________________________________
d) NaMnO4
___________________________________
e) CO
___________________________________
f) Al2O3
___________________________________
g) SnCl4
___________________________________
h) BH3
___________________________________
i) K3N
___________________________________
j) N2O
___________________________________
Writing Formulas from names
Write the formulas for the following compounds:
a) gold (I) cyanide
___________________________________
b) phosphorous pentachloride
___________________________________
c) lead (IV) oxide
___________________________________
d) tin (II) iodide
e) tetranitrogen pentoxide
___________________________________
___________________________________
Multiple Choice:
1. What is the Molar Mass of Magnesium sulfate heptahydrate?
A) 226.45
B) 120.37
C) 138.39
D) 246.47
E) 277.14
2. Calculate the number of moles of xenon in 12.0 g of xenon.
A) 1.00 mol
B) 0.0457 mol
C) 0.183 mol
D) 7.62 x 10–3 mol
E) 9.14 x 10–2 mol
3. What is the average mass, in grams, of one potassium atom?
a) 5.14 x 10–23 g
b) 6.49 x 10–23 g
c) 6.02  10–18 g
d) 31.0 g
e) 39.1 g
4. What is the mass of 7.80 x 1018 carbon atoms?
a) 1.30 x 10–5 g
b) 6.43 x 103 g
c) 7.80 x 1018 g
d) 1.56 x 10–4 g
e) 12.01 g
5. Determine the number of moles of aluminum in 96.7 g of Al.
a) 0.279 mol
b) 3.58 mol
c) 7.43 mol
d) 4.21 mol
e) 6.02 x 1023 mol
6. How many atoms are in 5.54 g of F2?
a) 6.02 x 1023 atoms
b) 0.146 atoms
c) 0.292 atoms
d) 8.78 x 1022 atoms
e) 1.76 x 1023 atoms
7. How many moles of NH3 are there in 77.5 g of NH3?
a) 0.220 mol
b) 4.55 mol
c) 14.0 mol
d) 1.31 x 103 mol
e) None of the above.
8. Calculate the molecular mass of potassium permanganate, KMnO4.
a) 52 amu
b) 70 amu
c) 110 amu
d) 158 amu
e) 176 amu
9. What is the mass of 0.0250 mol of P2O5?
a) 35.5 g
b) 5676 g
c) 0.0250 g
d) 1.51 x 1022 g
e) 3.55 g
10. How many sodium atoms are there in 6.0 g of Na3N?
a) 3.6 x 1024 atoms
b) 4.6 x 1022 atoms
c) 1.3 x 1023 atoms
d) 0.217 atoms
e) 0.072 atoms
11. How many moles of Cl atoms are there in 65.2 g CHCl3?
a) 0.548 mol
b) 1.09 mol
c) 3.3 x 1023 mol
d) 1.64 mol
e) 3.0 mol
12. The mass of four moles of molecular bromine (Br2) is
a) 80 g
b) 320 g
c) 640 g
d) 140 g
e) 24 x 1023 g
13. The empirical formula of a compound of uranium and fluorine that is composed of
67.6% uranium and 32.4% fluorine is
a) U2F
b) U3F4
c) UF4
d) UF6
e) UF8
14. A compound was discovered whose composition by mass is 85.6% C and 14.4% H.
Which of the following could be the molecular formula of this compound? (Hint: find the
EF first)
a) CH4
b) C2H4
c) C3H4
d) C2H6
e) C3H8
15. What is the coefficient of H2O when the following equation is properly balanced with the
smallest set of whole numbers?
___ Na + ___ H2O  ___ NaOH + ___ H2
a)
b)
c)
d)
e)
1
2
3
4
5
16. What is the coefficient preceding O2 when the following combustion reaction of a fatty
acid is properly balanced using the smallest set of whole numbers?
__ C18H36O2 + __ O2  __ CO2 + __ H2O
a)
b)
c)
d)
e)
1
8
9
26
27
17. Ammonia reacts with diatomic oxygen to form nitric oxide and water vapor:
4NH3 + 5O2  4NO + 6H2O
What type of chemical reaction is this according to the nature of the change?
a) double displacement
b) reduction oxidation
c) gas forming
d) single displacement
e) decomposition
18. How many grams of water could be made from 5.0 mol H2 and 3.0 mol O2?
a) 90 g
b) 36 g
c) 42 g
d) 45 g
e) 108 g
19. According to the following chemical reaction
2Al + Cr2O3  Al2O3 + 2Cr
a) aluminum metal displaces chromium metal from its oxide compound
b)
c)
d)
e)
aluminum metal displaces chromium(III) ion from its oxide compound
aluminum and chromium are in a double replacement reaction
Chromium (III) ion results from the reaction of Aluminum metal with Chromium oxide
None of these statements are right.
20. The percent composition by mass of an unknown chlorinated hydrocarbon was found to
be 37.83% C, 6.35% H, and 55.83% Cl by mass. What is the empirical formula of this
compound?
a)
b)
c)
d)
e)
C2H4Cl
C3H7Cl
C3H6Cl2
C4H9Cl
C5H11Cl
21. What is the formula for the ionic compound formed by calcium ions and nitrate ions?
a) Ca3N2
b) Ca(NO3)2
c) Ca2NO3
d) Ca2NO2
e) CaNO3
21. The formula for calcium phosphate is
a) CaPO4.
b) Ca3(PO4)2.
c) Ca2(PO4)3.
d) Ca3P2.
e) Ca3(PO3)2.
22. The correct name for NH4NO3 is
a) ammonium nitrate.
b) ammonium nitrogen trioxide.
c) ammonia nitrogen oxide.
d) hydrogen nitrogen oxide.
e) hydrogen nitrate.
23. The correct name for CuSO4·5H2O is
a) copper sulfate acid.
b) copper sulfate pentahydrate.
c) copper(II) sulfate acid.
d) copper(II) sulfate pentahydrate.
e) copper(V) sulfate hydrate.
24. The Stock system name for Mn2O7 is
a) dimanganese heptaoxide.
b) magnesium oxide.
c) manganese(VII) oxide.
d) manganese(II) oxide.
e) manganese(III) oxide.
25. Which of the following chemical equations represent oxidation-reduction reactions?
1) Zn(s) + CuSO4(aq)  ZnSO4(aq) + Cu(s)
2) SrO(s) + H2O(ª)  Sr(OH)2(aq)
3) AgNO3(aq) + NaI(aq)  AgI(s) + NaNO3(aq)
a.
b.
c.
d.
e.
1
2
1 and 2
1 and 3
2 and 3
26. Classify the reaction below.
FeCl3(aq) + 3 NaOH(aq)  Fe(OH)3(s) + 3 NaCl(aq)
a.
b.
c.
d.
e.
gas forming
oxidation-reduction
acid-base
Precipitation
Decomposition
Brief Answer/Calculations
26. Calculate the mass of 3.7 moles of Br2.
ANS: 3.7 mol Br2 x 159.8 g/mol = 591.26 g Br2
27. Calculate the volume of 0.15 mole of Br2. The density of Br2 is 3.12 g/mL.
ANS:0.15 mole x 159.8 g/mol x 1mL/ 3.12g = 7.68 mL
28. Define a mole in three different ways.
ANS: A quantity of matter whose mass is grams is numerically equal to its mass in
amu. (Add all the other definitions to this one – check the book and the powerpoint)
29. ANS: If 0.66 mole of a substance has a mass of 99 g, what is the molecular mass of
the substance?
Molecular mass = 99g / 0.66mole = 150g/mol translates to 150amu
30. Calculate the percent carbonate by mass in Na2CO3.
ANS: % = (mass CO3 / mass Na2CO3) x 100 = (60/125.99) x 100 = 47.62% CO3
31. When a 0.952 g sample of an organic compound containing C, H, and O is burned
completely in oxygen, 1.35 g of CO2 and 0.826 g of H2O are produced. What is the
empirical formula of the compound?
ANS Hint: Remember you need to get the
1. Calculate moles C from moles carbon dioxide and moles H from 2 x moles water
2. Change moles to g C and g H, total these and subtract from g sample to get g O
3. Calculate moles O from g O
4. Convert all the moles to whole numbers (Divide all by the least of them and/or find a
multiplier to get a whole number
32. Copper has two naturally occurring isotopes. A typical sample consists of 69.17%
(62.939598 amu) and 30.83%
(64.927793 amu). Calculate the atomic mass of copper.
33. Copper has two naturally occurring isotopes. A typical sample consists of Copper – 63
which is 69.17% in abundance (62.939598 amu) and the other is 30.83%
.
Calculate the mass of Copper – 65 to five decimal places if the average atomic mass of
copper is 66.55amu.
34. Challenge question: A chemistry student determined the empirical formula for titanium
sulfide (TixSy). To do so, she reacted titanium with excess sulfur in a crucible, and got the
following data:
Weight of empty crucible
11.120 g
Weight of titanium
8.820 g
Weight of crucible and
31.700 g
product
The unreacted sulfur vaporizes as a gas and only the titanium sulfide compound remains
as a solid. What is the empirical formula of titanium sulfide?
35. Write a proper chemical equation (include s, l, g or aq) for the reaction described as
follows:
Three mole of aluminum metal react with a mole of solid iron(III) oxide to produce two
moles iron metal and a mole of solid aluminum oxide.
ESSAY: Answers will be given in class on Monday during the review
1. Which of the following statements of Dalton's atomic theory are now proven to be incorrect? (Note:
String Theory excluded in this discussion)
1. Matter is made up of atoms.
2. Atoms are indivisible and indestructible.
3. All atoms of a given element are identical.
Give explanations as to why the selected statements are now considered incorrect
2. Rutherford’s experiment was critical to determining some important features of the atom.
Describe the experiment briefly and explain clearly how the conclusions that were made.
3. Who was Dmitri Mendeleev and what were his important contributions to the study of the
Elements? Why is this useful to scientists today?