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Period 2 Chemistry 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. 
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.
 

 5. 
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.
 

 6. 
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
 

 7. 
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
 

 8. 
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
 

 9. 
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
 

 10. 
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
 

 11. 
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
 

 12. 
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
 

 13. 
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
 

 14. 
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
 

 15. 
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
 

 16. 
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
 

 17. 
Which graph displays an incorrect composition relationship?
a.
Graph A
c.
Graph C
b.
Graph B
d.
All of the graphs are correct.
 

 18. 
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
 

 19. 
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%
 

 20. 
Avogadro's number of representative particles is equal to one ____.
a.
kilogram
c.
kelvin
b.
gram
d.
mole
 

 21. 
All of the following are equal to Avogadro's number EXCEPT ____.
a.
the number of atoms of bromine in 1 mol Brmc021-1.jpg
b.
the number of atoms of gold in 1 mol Au
c.
the number of molecules of nitrogen in 1 mol Nmc021-2.jpg
d.
the number of molecules of carbon monoxide in 1 mol CO
 

 22. 
How many moles of tungsten atoms are in 4.8 mc022-1.jpg 10mc022-2.jpg atoms of tungsten?
a.
8.0 mc022-3.jpg 10mc022-4.jpg moles
c.
1.3 mc022-7.jpg 10mc022-8.jpg moles
b.
8.0 mc022-5.jpg 10mc022-6.jpg moles
d.
1.3 mc022-9.jpg 10mc022-10.jpg moles
 

 23. 
How many atoms are in 0.075 mol of titanium?
a.
1.2 mc023-1.jpg 10-25
c.
6.4 mc023-4.jpg 10mc023-5.jpg
b.
2.2 mc023-2.jpg 10mc023-3.jpg
d.
4.5 mc023-6.jpg 10mc023-7.jpg
 

 24. 
Which of the following is NOT a true about atomic mass?
a.
The atomic mass is 12 g for magnesium.
b.
The atomic mass is the mass of one mole of atoms.
c.
The atomic mass is found by checking the periodic table.
d.
The atomic mass is the number of grams of an element that is numerically equal to the mass in amu.
 

 25. 
What is the molar mass of (NHmc025-1.jpg)mc025-2.jpgCOmc025-3.jpg?
a.
144 g
c.
96 g
b.
138 g
d.
78 g
 



 
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