(01/18/2008)
(Friday Jan 18)
1. Note that in the report for part 1D – INAA experiment, p 25 of lab
manual, point 2: You should report F’ not Fexp.. F’ numbers should all
be around 1 but probably not exactly 1. Most of you are using the F’ for
dead time correction (DT) equation 14 on page 16. One group may have to
use F’ based on equation 13 if the delay times were different for
standard and sample. Always use at least 4 significant figures
throughout the calculations and report the stoichiometric values for Na,
Ca and Al in the formula to at least 3 significant figures (don’t round
these values). For example, using sample numbers (not necessarily good
data), one might report: Na (0.287)Ca(0.258)Al(0.989)SiO4 * XH2O X comes
from the TGA experiment which you may or may not have done yet.
2. point 4: give the mole of each element per g of 5A zeolite, for
example, to put the stoichiometric values on the same basis.
3. page 26. under Discussion section: Point 2. Were any impurities
detected in the sample? If yes, what are they and what is the evidence
for this conclusion? Point 3. How do the experimental and nominal
(expected) stoichiometries compare? If they are different, give a
plausible scientific explanation why they differ. Point 4. Is the
calculated experimental formula charge balanced and mass balanced? If
not, what does this mean? How do the assumptions in the calculations
affect your conclusions? How might the efficiency of the calcium
exchange reaction affect this?
(Friday Jan 18) Some of you were not involved with the actual making of the 4A zeolite that was started at the end of last term and left to cure in an 80 degree oven over the break. Here is the background information that might be helpful when you calculate yields. Each 4A sample was prepared by mixing 100 mL of the sodium aluminate solution (solution A) with 100 mL of the sodium silicate solution (solution B) into the pp jar. These solutions were prepared as follows.
Solution A: 100 g of sodium metasilicate, nonahydrate, Na2SiO3 ⋅ 9 H2O (CAS Number 13517-24-3), and 100 mL of triethanolamine (2,2',2" -nitrilotriethanol) in 700 mL of millipore distilled water (some warming may be necessary). Filter solution through 0.45 μm pore size filter.
Solution B:
80 g of sodium aluminate (CAS Number 1302-42-7) and 100 mL of
triethanolamine in 700 mL of millipore distilled water, also
filtered as Solution A.
If you are rusty on using Excel, we have a spreadsheet tutorial
on the course
supplementals page.
There is also HyperChem file on the course supplementals page that is fun to view if you have some time. HyperChem is installed on the PC’s in room 311. You can get a feel for the unit cell size and a N2 molecule.
There are audio tapes and booklets in room 311 on parts PXRD and nitrogen sorption experiments.
If you are a graduating senior,
please take a few minutes and fill out the
chemistry majors exit survey
and let us know what you think about the chemistry major's
experience at OSU. Don't forget to get your picture taken before you
leave town! Call the Media Services office in the Valley
Library at 737-3411 (open 8-5, M-F)
to make an
appointment (at no cost to you).
We need your picture for the graduation boards that hang in the hallway
on first floor of Gilbert.