Version A: Instructions
Midterm is worth 59 points, There is no extra credit.
RIGHT NOW- fill in your ID number, the bubbles and your version letter on the answer sheet, do this now so you don’t
forget.
There are four versions of the exam. The difference in the multiple choice is the rearrangement of letters, and the short
answers are designed to look similar. If you copy, you are most likely copying the wrong answer, this makes cheating
even more pointless than normal, please don’t do it.
If you think someone nearby may be copying, or something is simply disturbing you, please let me know and we can
adjust people’s seats appropriately. Tell me as early as possible.
Be sure to sign the sign in sheet. This is my record that you attended the class. If you are not sitting in your assigned
seat for a reason approved by me, you’ll need to make sure to write the seat where you are actually sitting next to your
name.
You will also need to show your ID to the TA when you turn in your exam.
Only the answer sheet will be graded. You may (and should) keep the exam sheet. Go home, retake it, see
how you did . If you write any work on scrap paper, the question sheet or anywhere other than the space given, it will
not be graded and you will not get any credit for it. Do not write on the back of the sheets, do not write anything you
want graded anywhere other than the space given. I’d suggest writing in pencil or doing scratch work elsewhere and
then copying over.
Use your time wisely. Do problems you know first, do problems worth many points first.
Exams will be sent through eee dropbox. They will be graded the same day as you take it, and the grades will be posted
at least by the next morning, if not sooner. It will take a week or more to get the exams back to you depending on how
backed up the system is. I can’t make this go faster, it is completely out of my hands.
Finally, relax. At that point there is nothing that being stressed will do for you. So take a deep breath, pick up your
writing utensil and show me how amazing you are at chemistry!
AND PUT YOUR VERSION
POINTS
ON THE FRONT OF YOUR TEST OR YOU WILL LOSE 10
STP=O oC and 1 atm
Long Answer Problems- Partial Credit Allotted, please show
your work on the answer sheet to receive partial credit.
Chapter 1:
Question 1 A lamp rated at 40.0 J/sec emits violet light of
wavelength 420 nm. What is the energy of the photons?
How many photons of violet light can the lamp generate
in 2.0 sec?
4.73x10-`19 J 1.70x1020 photons
Question 2 The work function for chromium metal is
7.00x10-19J. What energy and wavelength of radiation
must be used to eject electrons with a velocity of
1.50x106 m/sec.
1.72x10-18J and 1.15x10-7m
Contain A holds 847 mL of an ideal gas A at 2.30 atm.
Container B holds 274 mL of ideal gas B at 4.80 atm. If the
gases are allowed to mix together what is the partial
pressure of each gas? What is the final pressure? Assume
the temperature doesn’t change and no reaction occurs.
1.86atm, 0.907 atm, 2.77 atm
Question 8:
A 5.0-L air sample containing H2S at 298K and 1atm is
treated with a catalyst to promote the reaction:
Question 3 Describe the difference between bonding and
anti-bonding orbitals. Be sure to describe the differences
in their formation. How their energy levels are related.
And which ones are filled first.
2H2S + O2  2H2O + 2Ssolid
Bonding is formed from constructive interference and
antibonding from destructive interference, bonding is
lower in energy and is filled first.
0.13mol, 0.64 or 64%
Chapter 2,3 and 5:
Question 4: For each of the following: O3, CH2O, SCNstate the electron and molecular geometry. Is it polar?
O3: e.g. trig planar, m.g. bent,
polar
CH2O: e.g. trig planar, m.g. trig planar, polar
SCN-: e.g. linear,
m.g. linear,
polar
Question 5: Draw the MO diagram of C2. Determine the
bond order, would C2- have a higher or lower bond order?
(hint: this is a final exam you need to aim for perfection in
these diagrams this time!)
3, lower. See book for diagram, points removed for all the
same things listed in midterm 2
Chapter 4:
Question 6: A sample of an ideal gas has a volume of 2.34
L at 286 K and 1.04 atm. Calculate the pressure when the
volume is 1.52 L and the temperature is 298K.
1.67 atm
Question 7:
If 3.2 g of solid S was collected, calculate the moles of H2S
and the volume percentage of H2S in the original sample.
Short Answer Problems- No partial credit
allotted, be sure to round to proper significant figures,
include all units and check for calculation mistakes. All
answer must be on the line in the answer sheet. No work
will be graded. Please do all work on scrap paper in the
back of this packet. Put only your answer on the sheet.
Chapter 1
1. Give the chemical formula from stannic sulfide:
SnS2
2. Give the name for SCl2: sulfur dichloride
3. Give the formula for disulfur decafluoride: S2F10
4. Give the molecular formula for Hydrochloric acid: HCl
5. Calculate the Energy of a photon with a wavelength
21 nm.
9.5x10-18J
6. Find the max of a campfire with a surface
temperature of 1007 C to 2 significant figures.
2.3x10-3mm or 2.3x10-6m
7. What is the effect of increasing the intensity of a
laser of a frequency greater the threshold frequency?
More electrons
8. What is the effect of increasing the frequency of a
laser of a frequency greater the threshold frequency?
Greater speed (or greater kinetic energy)
9. Determine the speed of a baseball that weighs 145
grams with a DeBroglie wavelength of 2.091*10-33 m.
2.19m/s
10. Calculate the minimum uncertainty in position of an
electron atom that has uncertainty in velocity of 1300
m/sec, when going at 26 x107m/sec.
4.5x10-8m/s
11. Calculate the energy of the emitted photon from the
n=3 to n=1 level to 3 significant figures.
+1.94x10-18m
12. Give the electron configuration for Molybdenum:
[Kr]5s14d5
13. Give the electron configuration for Mo+:
[Kr]4d5
14. Give the electron configuration for F-:
[He]2s2 2p6
15. Provide the correct order of increasing
electronegativity affinity for : Br, I, F
I, Br, F
16. Provide the correct order of increasing atomic
radius for the following: Li+, Be2+, F-, P3-, S2-,
Be2+, Li+, F-, S2-, P3Chapter 2, 3 and 5
17. Draw the lewis structure of CO2
18. Which is the most stable structure for POCl2. In one
or two words tell me why.
A)
wrong
B)
correct
O
O
P
P
Cl
Cl
Cl
Cl
Cl
Cl
19. What molecular geometry is SeCl2? bent
20. What is the molecular formula for the following.
O
Below is the (labelless) MO diagram of Oxygen. Use this
to answer questions 25 and 26.
O
O
OH
aspirin
C9H8O4
Use the following molecule to answer questions 21-22
25.
26.
27.
28.
29.
21. What is the hybridization on the circled molecule
labeled A: Sp2
22. What is the hybridization on the circled molecule
labeled B: sp2
23. What orbital does a sp hybridized atom use to form
sigma bonds?: sp
24. What orbital does a sp2 hybridized atom use to form
pi bonds? P
What is the Bond order of O2 : 2
What is the Bond order of O2- : 1.5
Is F2 paramagnetic or diamagnetic? diamagnetic
Does PCl5 have polar bonds? yes
Does PCl5 have a dipole? no
Chapter 4
30. A tank of He gas is pressurized to 3.5 atm to fill
balloons at 298K, with 2.0 moles, how big is the tank?
14L
31. Calculate the molar mass of an ideal gas if 560mL
have a mass of 1.10g at STP.
43.9g/mol
32. If 0.12 mols of a gas take up .33 L, what is the space
occupied by 1.3 mols of that same gas?
3.6L
33. What is the new pressure of a 0.45 L flexible
container of gas at 1atm when the volume is halved?
2atm
34. gaseous mixture contains 314.0 Torr of H2(g), 354.7
Torr of N2(g), and 378.9 Torr of Ar(g). Calculate the mole
fraction, X, of Argon.
0.367 or 36.7%
35. What room mean square velocity of Nitrogen gas at
344K?
553m/s
36. Calculate the relative rate of effusion between CO2
and N2 (in order as written)
0.79