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Chemistry
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College Chemistry Homework Help
College Chemistry Homework Help
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superman650
7/7/09
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This discussion will surround college chemistry homework help including posts concerning labs, exams, lectures, problems, etc.
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superman650
7/7/09
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Answer the following practice exam question:
A common way to prepare NO3, an important atmospheric gas, is by the decomposition of N2O5
by the equilibrium reaction:
N2O5 (g) ? NO3(g) + NO2(g)
At 300 ?C Kp = 4.96. Hint: you can solve the questions below in two ways, one of them
described in part c. You can use either way to solve parts (a) and (b).
(a) (12 points) In the experiment n atm of N2O5 (g) were used to prepare NO3.
Calculate the partial pressure of NO3, pNO3, in a mixture that has a total pressure at equilibrium of
Pt = 1.00 atm.
The full formatted answer to this question and related exam can be found in this CHEM exam on Course Hero. I have also provided the answer below:
Kp = PNO3PNO2/PN2O5=4.96
= =
N2O5 (g) ? NO3(g) + NO2(g)
Initial pp: n 0 0
Change: -x +x +x
Equilibrium: n -x x x
Pt = 1.00-(n -x) + x +x = n + x -> n = 1.00 -x -> n -x = 1.00 -2x
4.96 = x2/(1.00 -2x)
x2 + 9.92x - 4.96 = 0
Solving the quadratic equation gives: x = 0.477 atm = pNO3
Find more CHEM exams at coursehero.com
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superman650
7/7/09
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Here is a cool chemistry lab whose purpose is to perform the experiment that J.J. Thomson did in 1897 to discover the electrons charge to mass ratio:http://www.coursehero.com/file/83442/lab2/
First, I turned on the filament so that the electron beam hit the fluorescent screen. Then, I turned on the electron field. When setting the value of the electron field, the concentration of red electrons moved to -0.0374 m. By turning the magnetic field level to -0.113G, the red sport went back to 0m. Seeing that the magnetic field unit was gauss(G), I had to change it to an SI unit. The corresponding SI unit is the telsa(T), whereas 1T=10,000G. Then, I substituted the distance the beam was deflected for y. Then, I substituted E for the electric field and B for the magnetic field. Using L, which equals .10m, the length of the deflecting plate and equation x=2.0m for the distance, I found the mass ration of the electron(q/m). Read my data and analysis on the link above. Here you can find more chemistry labs http://www.coursehero.com/subjects/8-CHEMISTRY/
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