Chemistry 152 Final Exam A Key
Please put your name on this exam. Be sure to answer all of the questions as
completely as possible. Its been a kick! Best of luck in 200.
100 points
True / False (2 points)
1. In a controlled experiment we change one variable at a time.
True
False
2. The difference between a mixture and a compound is that in a compound there is more than
one set of properties.
True
False
3. Ionic bonds are the strongest types of bonds.
True
False
4. In a physical change, new substances are formed.
True
False
5. In an ideal gas, the volume of the gas particles themselves is significant.
True
False
Chemistry 152 Final A Key Pg. 2
Multiple Choice (4 Points each)
6. Which of the following are elements. (could be more than one)
a. ammonia
b. sodium
c. steel
d. titanium
e. water
7. An electron can be described as
a. a wave
b. a particle
c. a negatively charged cloud
d. all of these
e. none of these
8. As we go across a row on the periodic table
a. atomic radii increase and electronegativity increases
b. atomic radii increase and electronegativity decreases
c. atomic radii decrease and electronegativity increases
d. atomic radii decrease and electronegativity decreases
9. In a system at equilibrium,
a. the amount of reactants is equal to the amount of products.
b. the rates of the forward and reverse reactions is equal.
c. the ratio of products over reactants is 1.
d. the molarities of the products are equal to the molarities of the reactants.
10. The correct order of strength of intermolecular forces is:
a. H- bonds > dipole > nonpolar
b. dipole > H-bonds > nonpolar
c. dipole > nonpolar > H-bonds
d. nonpolar > dipole > H-bonds
Chemistry 152 Final A Key Pg. 3
Additional multiple choice
(3) 11. What is the mass of 3.30 × 1023 atoms of silver?
a. 5.90 X 10-9 g
b. 5.92 x 10-22 g
c. 53.1 g
d. 59.1 g
e. 0.548 g
3.30 X 1023 atoms X 1mole Ag X 107.87 g Ag = 59.1 g Ag
6.022 X 1023 atoms mole Ag
(5) 12. How many hydrogen atoms are in 5.0 g of acetone (C3H6O, 58 g/mol) ?
a. 5.2 × 1022 atoms
b. 3.1 × 1023 atoms
c. 1.8 × 1025 atoms
d. 2.4 × 1023 atoms
e. 3.0 × 1024 atoms
5.0 g X
1 mole acetone
58 g
X 6 mol H X 6.022 X 1023 H = 3.1 X 1023
mol acetone
mole H
(2) 13. How many moles of silver chloride are in 2.50 g of silver chloride (143.35 g/mol)
a. 0.0170 mol
b. 57 mol
c. 0.19 mol
d. 2.4 mol
e. 0.30 mol
2.50 g AgCl X 1 mole AgCl = 0.0174 mole AgCl
143.35 g AgCl
(3) 14. How many moles of oxygen gas react to yield 0.100 mol of water?
C5H12(g) + 8 O2(g)
a. 0.100 mol
b. 0.0750 mol
c. 0.600 mol
d. 0.800 mol
e. 0.133 mol

5 CO2(g) + 6 H2O(g)
Chemistry 152 Final A Key Pg. 4
0.100 mol H2O X 8 mol O2 = 0.133 mol O2
6 mol H2O
(12) 15. What mass of cobalt(III) sulfide (214.07 g/mol) is produced from 0.750 g of cobalt and
0.817 g of sulfur?
2 Co(s) + 3 S(s)  Co2S3(s)
a. 1.82 g
b. 1.36 g
c. 2.34 g
d. 2.72 g
e. 5.45 g
Have
Need
0.750 g Co X 1 mole Co = 0.0127 mol Co X 3 mol S = 0.0191 mol S
58.93 g Co
2 mol Co
0.817 g S X 1 mol S = 0.0255 mol S
32.06 g S
Cobalt is limiting
0.0127 mol Co X 1 mol Co2S3 X 214.07 g Co2S3 = 1.36 g Co2S3
2 mol Co
mol Co2S3
(5) 16. Describe the modern model of the atom. Be sure to include the masses, charges and
locations of all of the subatomic particles.
Protons: mass 1, charge 1, nucleus
Neutrons: mass 1, charge 0, nucleus
Electrons: negligible mass, charge -1, discrete orbitals very far from the nucleus
Chemistry 152 Final A Key Pg. 5
(10) 17. For each of the following give the number of protons, neutrons and an electron
configuration.
P
n
econfig
a. 65Zn
30
35
[Ar]4s23d10
b. 28Al
13
15
[Ne]3s23p
59
28
31
[Ar]3d8
c.
Ni2+
(10) 18. For each of the following, write a balanced chemical equation and, if possible, a net
ionic equation.
a. ammonium nitrate + sodium sulfide -
2 NH4NO3 + Na2S --- 2 NH3 + H2S + 2 NaNO3
2 NH4+ + S2- --- 2 NH3 + H2S
b. potassium phosphate + calcium chloride -
2 K3PO4 + 3 CaCl2 --- Ca3(PO4)2 + 6 KCl
2 PO43- + 3 Ca2+ --- Ca3(PO4)2
(5) 19. What volume of 0.054M sodium carbonate (105.99g/mol) contains 2.55g of sodium
carbonate?
2.55 g Na2CO3 X 1 mol Na2CO3 X 1L
= 0.445 L
105.99 g Na2CO3 0.054 mol Na2CO3
(5) 20. What is the volume of 0.066 moles of nitrogen gas at 25.0ºC and 1.25 atm?
V = nRT = 0.066mol(0.08206Latm/molK)298.2K = 1.3 L
P
1.25 atm
Chemistry 152 Final A Key Pg. 6
(5) 21. Show how a buffer made from ammonia and ammonium ion can neutralize both added
acid and added base.
NH3 + H+ --- NH4+
NH4+ + OH- --- NH3 + H2O
(5) 22. For the molecule below, draw a Lewis dot structure (include resonance if applicable).
Give the shape.
O3
<--->
O
O
bent
O
O
O
O