Chapter 7 Exam
____
1. What is the formula for the compound formed by lead(II) ions and chromate ions?
a. Pb2(CrO4)3
c. Pb(CrO4)2
d. PbCrO4
b. Pb2CrO4
____
2. What is the empirical formula for a compound that is 43.6% phosphorus and 56.4% oxygen?
a. P2O5
c. P2O3
b. PO3
d. P3O7
____
3. The empirical formula for a compound shows the symbols of the elements with subscripts indicating the
a. number of moles of the compound in 100 g.
b. atomic masses of each element.
c. smallest whole-number ratio of the atoms.
d. actual numbers of atoms in a molecule.
____
4. What is the formula mass of ethyl alcohol, C2H5OH?
a. 45.06 amu
c. 46.08 amu
b. 30.33 amu
d. 33.27 amu
____
5. A chemical formula for a molecular compound represents the composition of
a. the ions that make up the compound.
c. an atom.
b. a molecule.
d. the crystal lattice.
____
6. What is the formula for silicon dioxide?
a. S2O
b. Si2O
c. SiO2
d. SO2
7. Name the compound SiO2.
a. silicon oxide
b. silicon dioxide
c. silver oxide
d. monosilver dioxide
____
____
8. A compound's empirical formula is C2H5. If the formula mass is 58 amu, what is the molecular formula?
a. C3H6
c. C5H15
d. C4H10
b. C5H8
____
9. A molecular compound has the empirical formula XY3. Which of the following is a possible molecular
formula?
a. XY4
c. X2Y5
b. X2Y6
d. X2Y3
____ 10. A compound's empirical formula is HO. If the formula mass is 34 amu, what is the molecular formula?
a. HO3
c. H2O3
b. H2O2
d. H2O
____ 11. The percentage composition of sulfur in SO2 is about 50%. What is the percentage of oxygen in this
compound?
a. 90%
c. 25%
b. 75%
d. 50%
____ 12. A formula that shows the simplest whole-number ratio of the atoms in a compound is the
a. empirical formula.
c. ideal formula.
b. experimental formula.
d. molecular formula.
____ 13. The molar mass of an element is the mass of one
a. gram of the element.
c. mole of the element.
b. atom of the element.
d. crystal of the element.
____ 14. What is the formula for dinitrogen trioxide?
a. N2O6
b. Ni2O3
c. N2O3
d. NO3
____ 15. What is the empirical formula for a compound that is 31.9% potassium, 28.9% chlorine, and 39.2% oxygen?
a. K2Cl2O5
c. KClO3
b. KClO2
d. K2Cl2O3
____ 16. A compound contains 27.3 g of C and 72.7 g of O. What is the empirical formula for this compound?
a. CO2
c. C2O
b. C2O4
d. CO
____ 17. What is the percentage composition of CO?
a. 43% C, 57% O
b. 25% C, 75% O
c. 12% C, 88% O
d. 50% C, 50% O
____ 18. What is the mass percentage of chlorine in NaCl?
a. 50%
c. 35.45%
b. 60.7%
d. 64.5%
____ 19. What is the formula mass of magnesium chloride, MgCl2?
a. 46 amu
c. 59.76 amu
b. 95.21 amu
d. 106.35 amu
____ 20. What is the formula mass of (NH4)2SO4?
a. 114.09 amu
b. 118.34 amu
c. 128.06 amu
d. 132.16 amu
____ 21. The molar mass of CCl4 is 153.81 g/mol. How many grams of CCl4 are needed to have 5.000 mol?
a. 30.76 g
c. 769.0 g
b. 796.05 g
d. 5 g
____ 22. The molar mass of H2O is 18.02 g/mol. How many grams of H2O are present in 0.20 mol?
a. 35.9 g
c. 0.2 g
b. 89.9 g
d. 3.6 g
____ 23. What is the sum of the atomic masses of all the atoms in a formula for a compound?
a. molecular mass
c. actual mass
b. formula mass
d. atomic mass
____ 24. Name the compound Ni(ClO3)2.
a. nickel(II) chlorate
b. nickel(II) chloride
c. nickel(II) chlorite
d. nickel(II) peroxide
____ 25. The molar mass of MgI2 is
a. the sum of the masses of 1 mol of Mg and 1 mol of I.
b. the sum of the masses of 1 atom of Mg and 2 atoms of I.
c. the sum of the masses of 1 atom of Mg and 1 atom of I.
d. the sum of the masses of 1 mol of Mg and 2 mol of I.
____ 26. How many oxygen atoms are there in 0.500 mol of CO2?
a. 15.9994
c. 6.02 1023
23
b. 3.01 10
d. 11.0
____ 27. What is the formula for the compound formed by calcium ions and chloride ions?
a. CaCl2
c. Ca2Cl
d. CaCl
b. CaCl3
____ 28. What is the percentage composition of CuCl2?
a. 33% Cu, 66% Cl
c. 65.50% Cu, 34.50% Cl
b. 47.27% Cu, 52.73% Cl
d. 50% Cu, 50% Cl
____ 29. The molecular formula for vitamin C is C6H8O6. What is the empirical formula?
a. C3H4O3
c. CH2O
b. CHO
d. C2H4O2
____ 30. What is the empirical formula for a compound that is 36.1% Ca and 63.9% Cl?
a. Ca2Cl
c. Ca2Cl2
b. CaCl
d. CaCl2
____ 31. The formula for carbon dioxide, CO2, can represent
a. one molecule of carbon dioxide.
b. the combination of 1 atom of carbon and 2 atoms of oxygen.
c. 1 mol of carbon dioxide molecules.
d. all of the above.
____ 32. Name the compound Zn3(PO4)2.
a. zinc phosphite
b. zinc potassium oxide
c. trizinc polyoxide
d. zinc phosphate
____ 33. A chemical formula includes the symbols of the elements in the compound and subscripts that indicate
a. atomic mass of each element.
b. formula mass.
c. number of atoms or ions of each element that are combined in the compound.
d. charges on the elements or ions.
____ 34. What is the formula for sulfur dichloride?
a. SCl
b. SCl2
c. S2Cl2
d. S2Cl
____ 35. To find the molecular formula from the empirical formula, one must determine the compound's
a. structural formula.
c. crystal lattice.
b. density.
d. formula mass.
36. EXTRA CREDIT:
In one graph; designate NaCl, CO2 and AgBr on a graph comparing an increasing numerical variation
between the percent compositions as a function of atomic decreasing electronegativity differences and as a
function of atomic increasing radius differences. When calculating the differences do so by contrasting the
atoms within each compound. Utilize the generalized periodic trends.
Chapter 7 Exam
Answer Section
1. ANS: D
OBJ: 2
2. ANS: A
Solution:
PTS: 3
DIF: III
REF: 1
PTS: 3
3. ANS: C
OBJ: 1
4. ANS: C
OBJ: 1
5. ANS: B
OBJ: 1
6. ANS: C
OBJ: 5
7. ANS: B
OBJ: 4
8. ANS: D
Solution:
DIF: III
PTS: 3
REF: 4
DIF: I
OBJ: 2
REF: 4
PTS: 3
DIF: III
REF: 3
PTS: 3
DIF: I
REF: 1
PTS: 3
DIF: II
REF: 1
PTS: 3
DIF: II
REF: 1
PTS: 3
9. ANS: B
OBJ: 3
10. ANS: B
Solution:
DIF: III
PTS: 3
REF: 4
DIF: II
OBJ: 4
REF: 4
PTS:
11. ANS:
OBJ:
12. ANS:
DIF: III
PTS: 3
REF: 4
DIF: II
OBJ: 4
REF: 3
PTS: 1
DIF: I
REF: 4
3
D
4
A
OBJ: 1
13. ANS: C
OBJ: 1
14. ANS: C
OBJ: 5
15. ANS: C
Solution:
PTS: 3
DIF: I
REF: 3
PTS: 3
DIF: II
REF: 1
PTS: 2
16. ANS: A
Solution:
DIF: III
REF: 4
OBJ: 2
PTS: 3
17. ANS: A
Solution:
DIF: III
REF: 4
OBJ: 2
PTS: 3
18. ANS: B
Solution:
DIF: III
REF: 3
OBJ: 4
PTS: 3
DIF: III
REF: 3
OBJ: 4
19. ANS: B
OBJ: 1
20. ANS: D
OBJ: 1
21. ANS: C
Solution:
PTS: 3
DIF: III
REF: 3
PTS: 1
DIF: III
REF: 3
PTS: 3
22. ANS: D
Solution:
DIF: III
REF: 3
OBJ: 2
PTS: 3
23. ANS: B
OBJ: 1
24. ANS: A
OBJ: 3
25. ANS: D
OBJ: 1
26. ANS: C
Solution:
DIF: III
PTS: 3
REF: 3
DIF: I
OBJ: 2
REF: 3
PTS: 3
DIF: III
REF: 1
PTS: 3
DIF: II
REF: 3
PTS: 3
27. ANS: A
OBJ: 2
28. ANS: B
Solution:
DIF: III
PTS: 3
REF: 3
DIF: III
OBJ: 3
REF: 1
PTS: 3
29. ANS: A
OBJ: 3
30. ANS: D
Solution:
DIF: III
PTS: 3
REF: 3
DIF: III
OBJ: 4
REF: 4
31.
32.
33.
34.
35.
36.
PTS:
ANS:
OBJ:
ANS:
OBJ:
ANS:
OBJ:
ANS:
OBJ:
ANS:
OBJ:
ANS:
3
D
1
D
3
C
1
B
5
D
3
DIF: III
PTS: 3
REF: 4
DIF: II
OBJ: 2
REF: 1
PTS: 3
DIF: III
REF: 1
PTS: 3
DIF: I
REF: 1
PTS: 3
DIF: II
REF: 1
PTS: 3
DIF: II
REF: 4
y
5
4
3
2
1
–5
–4
–3
–2
–1
–1
–2
–3
–4
–5
PTS: 5
1
2
3
4
5
x