Download take home 2 Fall 2004

Chem 131
Mixon
Name________________________________
Exam 1 – Take Home Portion
Due October 25th , 2004 in class
TAKE-HOME EXAM STATEMENT OF ACADEMIC HONESTY
(this statement MUST be signed and turned in with the exam in order to receive credit for this exam)
I declare that the answers contained within this exam are mine and mine alone. I agree that
while I may work on this exam with text resources, I may NOT seek help or guidance from any
other person. This includes current students, former students, students in other classes,
scientists, relatives, industry personnel, and anybody else in the universe. The only person I
may ask questions of is my instructor, April Mixon, however I understand that she reserves the
right to not provide me with answers to my questions. I understand that the answers that I put
down on this exam must be my own, in my own words, created by me.
I further understand that if I submit answers that are too similar to another person’s in
this class, or are downright plagiarized from any other person or source (printed or electronic),
that I will receive a zero on this exam (which will be included, in the total score, with my grade
on the in-class portion of the final exam). I also understand that if I fail to show my work, I will
receive no credit for my answers. This means that if a number is NOT given to me on the exam,
I understand that I need to show where my calculated number came from.
Signed:_____________________________________________________________________
Exam 2 – CH131
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Take Home Exam 2
Answer ALL questions on a separate sheet or insert returns before performing work!
SHOW ALL WORK!!!! SHOW ALL WORK!!!! SHOW ALL WORK!!!! SHOW ALL WORK!!!!
NO WORK, NO CREDIT!!!!!!!! NO WORK, NO CREDIT!!!!!!!! NO WORK, NO CREDIT!!!!!!!!
1.
Suppose 12.25 grams of propane gas (CH3CH2CH3) is burned in a plentiful supply of oxygen.
a. Write the balanced equation with states of matter AND products for this reaction (2pts)
b. How many moles of oxygen are consumed in this reaction?(2pts)
c. Suppose you need to make 150 ml of water (d=1.01 grams/mL), how many grams of each reactant
would you need? (3 pts)
2.
When Joseph Preistly, the discoverer of oxygen gas, did his work, he decomposed mercury (II) oxide, HgO,
by heating it to produce oxygen gas. If 64.21 grams of mercury is obtained from 80.45 grams of the oxide,
what is the percent yield of this reaction? (6 pts)
3.
Given the following table, fill in the missing values. Show all work and DO not use solved values to
calculate other missing values. (9 pts)
Energy (J)
Frequency (Hz)
Wavelength (nm)
722
Region of Spectrum
6.349 x 1014
1.655 x 10-13
4.
5.
6.
7.
8.
Why could the Bohr model not predict spectral lines for atoms other than Hydrogen? (2 pts)
A transition in the Hydrogen atom results in an energy of 4.086 x 10 -19 J. If the electron falls to n=2, what
energy level did it fall from? What frequency and what wavelength is this? What region of the EM
spectrum does it correspond to? (5 pts)
Explain what is meant by energy being quantized and why there are certain lines in an emission spectrum
(e.g. the spectrum is not continuous) (4 pts)
Starting with solid sodium sulfate, describe how you would prepare 1.33 L of a 2.45 M solution. (3 pts)
Indicate whether or not the following quantum numbers are valid, if there is an error, write a valid set of
quantum numbers keeping n and ml constant: (4 pts)
a. n= 3 l = 3 ml = 2
b. n= 5 l = 0 ml = 0
c. n= 2 l = 4 ml = 0
d. n= 3 l = 2 ml = -2
Exam 2 – CH131
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