Chemistry CP Final Exam Review #2
Chapter 10: Energy
Define the following terms: energy, potential energy, kinetic energy, radiant energy, Law of
conservation of energy, state function, temperature, heat, exothermic reaction, endothermic
reaction, calorie, specific heat, enthalpy, calorimeter, Hess’s Law, fossil fuels, petroleum,
natural gas, coal, greenhouse effect, entropy
Problems:
Use the specific heat equation to compete the following problems.
Q = m x C x T
(Remember: C = 4.184 J/g*C for water)
1. The temperature of a metal bar with a mass of 87 grams is raised from 31oC to 132oC. In
the process, 790.0 Joules of heat were absorbed. Find the specific heat of the metal.

790.0 J  87 g C  132 o C  31o C

C = 0.090 J/g*C
2. How much heat is required to raise the temperature of an 18.7 gram sample of platinum
by 2.3oC if the specific heat of platinum is 1.3 J/g.oC?

J 
q  18.7 g 1.3 o  2.3o C
 g* C 


q = 56 J
3. A 23.6 g sample of metal, originally at 88.0oC, was places in 62 grams of water originally
at 17.0oC. After some time, the system reached equilibrium and the final temperature of
the system was 21.5oC. Find the specific heat of the metal.
qmetal = qwater

23.6 g C 88.0 o C  21.5o C   62 g  4.184

C = 0.74 J/g*C
J 
 21.5 o C  17.0C
o
g C 


Use Hess’s Law to complete the following problems.
4. Calculate the Enthalpy change for the reaction, N2 (g) + 2 O2 (g)  2 NO2 (g) , given the
information below.
N2 (g) + O2 (g)  2 NO(g)
H = 180 kJ
2NO(g) + O2 (g)  2 NO2 (g)
Add reactions
N2 + 2 O2  2 NO2
H = -112 KJ
H = 68 kJ
5. Find the H for the reaction: 2 Cu(s) + O2 (g)  2 CuO(s)
reverse reaction
reverse and X 2
4 CuO(s)  2 Cu2O(s) + O2 (g)
Cu2O(s)  Cu(s) + CuO(s)
2 Cu2O + O2  4 CuO
H = 288 kJ
H = 11 kJ
H = -288 kJ
2 CuO + 2 Cu  2 Cu2O H = -22 kJ
__________________________________________
2 Cu + O2  2 CuO
H = -310 kJ
Complete the following heat and stoichiometry problems:
6. Nitrogen reacts with hydrogen to produce ammonia (NH3). Ho = -46.2 kJ. How many kJ of
heat is absorbed when 97 grams of NH3 is produced? (Hint: write the reaction first.)
N2 + 3 H2  2 NH3

1 mol NH 3   46.2 kJ 

  130 kJ
 17.0305 g NH 3  2 mol NH 3 
97 g 
7. How much heat is transferred when 9.22 grams of glucose (C6H12O6) in your body reacts
with O2 to produce CO2 and H2O? (Ho = -2500 kJ) (Hint: write the reaction first.)
C6H12O6 + 6 O2  6 CO2 + 6 H2O

1 mol C6 H 12O6   2500 kJ 

  130 kJ
180
.
158
g
C
H
O
1
mol
C
H
O
6
12 6 
6
12 6 

9.22 g C6 H12O6 
Chapter 11: Modern Atomic Theory
Define the following terms: electromagnetic radiation, wavelength, frequency, photons,
quantized, line spectrum, continuous spectrum, orbital, principal energy levels, sublevels,
electron configuration, orbital diagram, valence electrons, core electrons, representative
elements, metals, nonmetals, metalloids, atomic size, ionization energy
1. Describe the Rutherford model of the atom
The Rutherford model of the atom consists of a centrally located nucleus, which contains most of
the atom’s mass including the positively charged protons and neutral neutrons. Negatively
charged electrons orbit the nucleus in circular paths. The number of protons and electrons is
equal and the atom is mostly empty space.
2. Describe the Bohr model of the atom.
The Bohr model of the atom describes a positively charged nucleus with negatively charged
electrons traveling in circular orbitals, which correspond to distinct energy levels. When
excited, electrons can move to higher energy level orbits.
3. Describe the Wave-mechanical model of the atom
The Wave-mechanical model of the atom treats the electrons as particles, which move in the
form of a wave. The electrons are located outside of the nucleus and travel randomly throughout
atomic orbitals. These orbitals describe regions of space in which the probability of finding an
electron is likely.
4. Draw orbital diagrams for the following elements and determine the number of unpaired
electrons.
a. Magnesium
Draw with boxes for oribtals and arrows representing electrons!
12 electrons, 0 unpaired
b. Oxygen
8 electrons, 2 unpaired
c. Aluminum
d. Argon
13 electrons, 1 unpaired
18 electrons, 0 unpaired
e. Scandium
21 electrons, 1 unpaired
5. Write electron configurations for:
a. Lead
1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p2
b. Nickel 1s22s22p63s23p64s23d8
6. Describe the trends on the periodic table for atomic size and explain why elements follow
these trends.
Atomic Size increases going down a group on the periodic table and decreases going left to
right across the periodic table. As you go down a group the outer electrons are in successively
higher energy levels and, therefore, larger orbitals. As you go left to right across a period,
elements contain outer electrons in the same energy level. However, the number of protons
increases, resulting in a greater attraction for the outer electrons and making the atoms smaller.
7. Describe the trends on the periodic table for ionization energy and explain why elements
follow these trends.
Ionization energy increases as you go up a group on the period table and left to right
across the periodic table. Moving up a group, the I.E. increases because outer electrons are
in smaller orbitals and, therefore, closer to the nucleus and held more strongly. As you go
left to right, the I.E. increases because the number of protons in the nucleus is increasing.
This results in a greater positive charge that attracts outer electrons.
It can also be explained in terms of size. The smaller the atom is, the larger the
ionization energy. As atoms get smaller the outer electrons can be closer to the nucleus and
attracted strongly to the nucleus.
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Chemistry CP Final Exam Review #2