Chemical Principles I, First Exam
Name:______________________
All calculations must be CLEARLY shown to receive ANY credit for questions.
1. (6 pts) Carry out the following operations.
a.
2.453 + 13.21 + 0.0268
b.
89.03 / 34.86783
c.
3.41 – 0.23 x 0.405
2. (6 pts) Indicate the number of significant figures.
a.
0.0002030 g
b.
2.000000 cm
c.
8.00600 mL
3. (6 pts) Give the number of electrons, protons, and neutrons for the following atoms or ions.
electrons
protons
neutrons
–
81
35 Br
39 
19 K
99
43Tc
4. (12 pts) Name the following ionic compounds:
a.
(NH4)2SO4
b.
Mg(ClO4)2
c.
Cu(NO3)2
d.
K2CO3
e.
Hg2S
f.
Fe(OH)3
Test 1, Chapters 1-3, Chemical Principles I, Fall 03
1
5.
(10 pts)Write the chemical formulas for the following compounds:
a.
silver oxide
b.
zinc phosphate
c.
aluminum sulfate
d.
sodium hypobromite
e.
lithium sulphate
6.
(10 pts) Balance the following equations:
a.
Hg(NO3) 2 
b.
C5H10 +
HgO +
O2

NO2 +
CO2
+
O2
H2O
Test 1, Chapters 1-3, Chemical Principles I, Fall 03
2
7.
A compound’s mass is found to be 24.5% Na, 14.9% Si, and 60.6% F.
Calculate its empirical formula. (10 pts)
Test 1, Chapters 1-3, Chemical Principles I, Fall 03
3
8.
Butyne C4H6 is combusted to form CO2 and H2O. Calculate the maximum mass of CO2
formed when 1.00g of butyne is combusted. (12 pts)
Test 1, Chapters 1-3, Chemical Principles I, Fall 03
4
9.
50.0g of ethylene oxide are mixed with 100.0g of oxygen and allowed to react according
to the chemical equation:
2 C2H4O + 5 O2  4 CO2 + 4 H2O
Calculate the maximum mass of CO2 produced. (18 pts)
Test 1, Chapters 1-3, Chemical Principles I, Fall 03
5
10.
Aluminum sulfide, Al2S3 reacts with water to form aluminum hydroxide, Al(OH)3 and
hydrogen sulfide gas, H2S according to the following chemical equation:
Al2S3 (s) + 6 H2O (l)  2 Al(OH)3 (s) + 3 H2S (g)
Calculate the percent yield when 45.7 g of Al(OH)3 are recuperated after 50.0 g of Al2S3 are
completely reacted (9 pts.). State two factors which affect the percent yield. (1 pt.)
Test 1, Chapters 1-3, Chemical Principles I, Fall 03
6
Test 1, Chapters 1-3, Chemical Principles I, Fall 03
7