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Chapter 6 Prep Test

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 1. 
The number of atoms in a mole of any pure substance is called
a.
its atomic number.
c.
its mass number.
b.
Avogadro’s number.
d.
its gram-atomic number.
 

 2. 
What can be said about 1 mol Ag and 1 mol Au?
a.
They are equal in mass.
b.
They contain the same number of atoms.
c.
Their molar masses are equal.
d.
They have the same atomic mass.
 

 3. 
An Avogadro’s number of any element is equivalent to
a.
the atomic number of that element.
c.
6.022 ´ 1023 particles.
b.
the mass number of that element.
d.
12 g of that element.
 

 4. 
Using a periodic table, what is the average atomic mass of zinc?
a.
69.723 amu
c.
63.546 amu
b.
58.693 amu
d.
65.39 amu
 

 5. 
A formula that shows the simplest whole-number ratio of the atoms in a compound is the
a.
molecular formula.
c.
structural formula.
b.
ideal formula.
d.
empirical formula.
 

 6. 
To determine the molar mass of an element, one must know the element’s
a.
Avogadro number.
c.
number of isotopes.
b.
atomic number.
d.
average atomic mass.
 

 7. 
What is the molar mass of magnesium?
a.
12.00 g
c.
24.305 g
b.
26.982 g
d.
22.990 g
 

 8. 
What is the empirical formula for a compound that is 31.9% potassium, 28.9% chlorine, and 39.2% oxygen?
a.
KClO2
c.
K2Cl2O3
b.
KClO3
d.
K2Cl2O5
 

 9. 
A compound contains 64 g of O and 4 g of H. What is the empirical formula for this compound?
a.
H2O
c.
H4O4
b.
H2O2
d.
HO
 

 10. 
A molecular compound has the empirical formula XY3. Which of the following is a possible molecular formula?
a.
X2Y3
c.
X2Y5
b.
XY4
d.
X2Y6
 

 11. 
A compound’s empirical formula is NO2. If the molecular mass is 92 amu, what is the molecular formula?
a.
NO
c.
NO2
b.
N2O2
d.
N2O4
 

 12. 
What is the sum of the atomic masses of all the atoms in a formula for a compound?
a.
ionic mass
c.
atomic mass
b.
molar mass
d.
actual mass
 

 13. 
What is the molar mass of ethyl alcohol, C2H5OH?
a.
30.33 amu
c.
45.06 amu
b.
33.27 amu
d.
46.08 amu
 

 14. 
The molar mass of LiF is 25.94 g/mol. How many moles of LiF are present in 10.37 g?
a.
0.3998 mol
c.
2.500 mol
b.
1.333 mol
d.
36.32 mol
 

 15. 
How many oxygen atoms are there in 0.500 mol of CO2?
a.
6.02 mc015-2.jpg 1023
c.
15.9994
b.
3.01 mc015-3.jpg 1023
d.
11.0
 

 16. 
If 0.500 mol of Na+ combines with 0.500 mol of Cl– to form NaCl, how many formula units of NaCl are present?
a.
3.01 mc016-2.jpg 1023
c.
6.02 mc016-4.jpg 1024
b.
6.02 mc016-3.jpg 1023
d.
1
 

 17. 
What is the percentage composition of CuCl2?
a.
33% Cu, 66% Cl
c.
65.50% Cu, 34.50% Cl
b.
50% Cu, 50% Cl
d.
47.27% Cu, 52.73% Cl
 

 18. 
The empirical formula is always the accepted formula for a(n)
a.
atom.
c.
molecular compound.
b.
molecule.
d.
ionic compound.
 

 19. 
The abbreviation for atomic mass unit is
a.
amu.
c.
a.
b.
mu.
d.
m.
 

 20. 
The mass of two moles of oxygen atoms (atomic mass 16 amu) is
a.
16 g.
c.
48 g.
b.
32 g.
d.
64 g.
 

 21. 
How many moles of atoms are in 50.15 g of mercury (atomic mass 200.59 amu)?
a.
0.1001 mol
c.
0.2500 mol
b.
0.1504 mol
d.
0.4000 mol
 

 22. 
The molar mass of MgI2 is
a.
the sum of the masses of 1 mol of Mg and 2 mol of I.
b.
the sum of the masses of 1 mol of Mg and 1 mol of I.
c.
the sum of the masses of 1 atom of Mg and 2 atoms of I.
d.
the sum of the masses of 1 atom of Mg and 1 atom of I.
 

 23. 
What is the empirical formula for a compound that is 53.3% O and 46.7% Si?
a.
SiO
c.
Si2O
b.
SiO2
d.
Si2O3
 

 24. 
What is the molecular formula of a compound that has a molar mass of 50.48 g/mol and an empirical formula of CH3Cl?
a.
CHCl
c.
CH3Cl
b.
CH2Cl
d.
CH2Cl2
 

 25. 
The molar mass of CS2 is 76.15 g/mol. How many grams of CS2 are present in 10.00 mol?
a.
0.13 g
c.
10.00 g
b.
7.614 g
d.
761.5 g
 

 26. 
The molar mass of NH3 is 17.03 g/mol. How many moles of NH3 are present in 107.1 g?
a.
0.1623 mol
c.
6.289 mol
b.
3.614 mol
d.
107.1 mol
 

 27. 
What is the mass of 0.240 mol glucose, C6H12O6?
a.
24.0 g
c.
180.16 g
b.
43.2 g
d.
750. g
 

 28. 
How many Cl– ions are present in 2.00 mol of KCl?
a.
1.20 mc028-2.jpg 1024
c.
2.00
b.
6.02 mc028-3.jpg 1024
d.
0.5
 

 29. 
Which of the following compounds have the same empirical formula?
a.
NO2 and N2O5
c.
C5H10 and C3H6
b.
SO3 and NO3
d.
H2O and H2O2
 
 
nar001-1.jpg
 

 30. 
A farmer makes up a new counting unit called a “cluckster.”
If the farmer had 3 clucksters of chicken eggs and 3 clucksters of quail eggs, what could you say about the ratio of their masses?
a.
The clucksters of chicken eggs will be 16 times heavier than the 3 clucksters of quail eggs
c.
The clucksters of quail eggs will be 16 times heavier than the 3 clucksters of chicken eggs
b.
The clucksters of chicken eggs will be 3 times heavier than the 3 clucksters of quail eggs
d.
The clucksters of chicken eggs will be  438 times heavier than the 3 clucksters of quail eggs
 
 
Use the following passage and graphs to answer the following three questions.
To practice solving percentage composition problems, a student made a series of circle graphs showing the composition of a sample of carbon dioxide (CO2). Graph A is based on a sample that is 100% CO2. Graph B represents the mass fractions of a 100.0-g sample of CO2. Graph C represents the mass fractions of a 23.5-g sample of CO2.
nar002-1.jpg
 

 31. 
Which graph displays an incorrect composition relationship?
a.
Graph A
c.
Graph C
b.
Graph B
d.
All of the graphs are correct.
 

 32. 
Based on the data shown in Graph C, how many atoms of carbon are there in a 23.5-g sample of CO2?
a.
2.26 X 1023 atoms
c.
6.02 X 1023 atoms
b.
3.21 X 1023 atoms
d.
1.18 X 1024 atoms
 

 33. 
What percentage (on a mass basis) of the sample in Graph C is oxygen (O2)?
a.
6.41%
c.
27.28%
b.
23.49%
d.
72.72%
 

 34. 
A molecule’s molecular structure composition is represented by
a.
an atom.
c.
the net ionic equation.
b.
a chemical formula.
d.
a lettuce with crystal.
 

 35. 
What is the molar mass of mc035-1.jpg?
a.
142 g/mol
c.
322.0 g/mol
b.
140.0 g/mol
d.
25,000 g/mol
 



 
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