CHM 101
GAGE
SPRING 2006
NAME ___________________________
SECTION ________________________
EXAM 2
SHOW WORK TO RECEIVE CREDIT FOR PROBLEMS.
1.
Supply the most appropriate word, phrase or numerical value for each of the following
statements.
(14)
a. simple atom diagram for bromine
a. (write on line below)
______________________________________________________________________
b. number of electrons possible on 4th atomic shell
b. ______________________
c. two interconvertible forms of energy
c. ______________________
______________________
2.
d. energy to remove an electron from a neutral atom
d. _____________________
e. number of electrons in a 3d orbital
e. ______________________
f. 345 K in oC
f. ______________________
g. type of bonding in MgSO4
g. _____________________
a. Match the symbol for the atoms listed here with their first ionization energies in
kJ/mol. Justify your choices with explanations for your selections.
(8)
P
Ca
________
403
________
588
Cl
Rb
O
________
1012
________
1251
________
1314
b. Place the following atoms in order from lowest to highest atomic radius and explain
the reason(s) for the order.
(8)
Cl
Sr
Ni
Mg As
_____
1
_____
_____ _____
_____
3.
Analysis of a compound reveals that it contains 1.31 g of phosphorus and 1.69 grams of
oxygen. The molar mass of the compound is 282 ± 3 g/mol. Determine the simplest and
molecular formulas for the compound.
(12)
600
4.
500
Energy (kJ)
400
300
200
100
0
0
2
4
6
8
10
12
Reaction Progress (sec)
The reactants in a chemical change have 487 kJ of energy. The change they undergo has
a H = -157 kJ. The activation energy for the reaction is 570 kJ.
a. Draw the energy vs reaction progress graph on the axes above paying attention to all
values. Label a point that represents all products and one that represents all reactants.
(10)
b. What factor is probably driving the reaction, lower energy or greater disorder?
Explain your choice.
(4)
2
5.
Bohr developed a model of the atom that looks like our planetary system. Explain what
the model is and how he arrived at this design.
(5)
6.
For the following substances provide the Lewis dot structure, the structural formula, and
the bond dipoles (on the structural formula). Indicate if the substance can show
resonance.
(15)
Substance
Lewis dot structure
Structural formula
Resonance?
with bond dipoles
Yes or No
CH2Cl2
AsO3-
COHCl
3
7.
Use the equation here to answer a-d below.
C7H12 + 2 H2O 
H = -254 kJ
C7H14(OH)2
a.
How many grams of C7H14(OH)2 can be formed from 6.0 x 1023 molecules of
H2O?
(8)
b.
How many grams of C7H14(OH)2 will form during the reaction of 53 grams C7H12
of and 150 grams of H2O?
(10)
c.
How many kJ are exchanged when 19.5 grams of H2O react with excess C7H12?
(6)
4