December 14 2015 7 5 points assuming methane behaves

December 14, 2015
7) (5 points) Assuming methane behaves as an ideal gas, what is the pressure of methane (in atm) in a closed
container at 145.0 ˚C, if the container was ini7ally filled and closed with 1.12 atm of pressure at 25.0 ˚C?
Pressure = ___________ atm
8) (6 points) Assuming an ideal gas, calculate the density in g/cm
3
of propane (C 3 H 8 ) at 0.000 ˚C and 1.000 atm.
Please give the answer in g/cm
3
and with 3 significant figures.
Density of propane = _________________ g/cm
3
9) (3 points) a) Draw the Lewis structure (including all bonds and all non-­‐bonding electron pairs/lone pairs) of SO
2
Cl
2
that follows theoctet rule . (Hint: S is the central atom). Determine the number of valence electrons in the molecule.
Predict the ideal bond angles and molecular geometry according to the VSEPR method for the sulfur atom.
b) Total valence electrons (1 point): ____________
c) Molecular geometry around the S atom (1 points): ______________
d) Ideal bond angle of O-­‐S-­‐O (1 points):__________
e) (2 points) Draw the Lewis structure of SO
2
Cl
2
that minimizes formal charges. (This structure does not have to follow
the octet rule).

December 14, 2015
10) (4 points) Given on the right is the molecular orbital diagram of N 2
a) What is the bond order of N
2
according to the molecular orbital diagram?
Bond order of N
2
: _______
b) Looking at the MO diagram, is the N 2 molecule diamagne7c or paramagne7c?
N
2
is ____________
11. (6 points) Calculate the energy, and frequency of the photon absorbed by the transi7on of a hydrogen electron from n=1
to n=3?
energy: ______________
frequency: _____________

December 14, 2015
12. (3) An atom of the isotope bromine-­‐81 consists of how many protons,
neutrons, and electrons?
(p = proton, n = neutron, e = electron)
13. (2) What is the name of N 2 O 5 ?
14. (2) The chemical formula for iron(III) nitrate is
15. (3) In which of the following pairs is the oxida7on number for the underlined element incorrect?
A) Br O 4
-­‐
/(+7) B) C O 3
2-­‐
/(+4) C) Fe O/(+2) D) I O 3
-­‐
/(+5) E) Mg (OH) 2 /(+3)