Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: johnnyjohn993123 on July 08, 2016, 02:16:36 AM
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Pipet 2.50 mL of the iron solution into five large test tubes. Add 2.50 mL of
the acetate buffer, 0.50 mL of the hydroxylamine hydrochloride solution and
mix. Pipet 0.50, 1.00, 1.50, 2.00 and 2.50 mL of the 5.00 x10-4 M
phenanthroline solution. Dilute to a total volume of 15 mL with water. Stand
for 10 min then measure absorbance.
*Iron solution conc= 5.0x10-4M
Repeat procedure except that you should use 5.00 mL of 1.50 x10-3 M
phenanthroline solution and 0.25, 0.50, 0.75, 1.00 and 1.25 mL of the iron
solution.
Plot absorbance versus iron concentration (M) and absorbance versus
phenanthroline concentration (M). From the slopes of these 2 graphs,
calculate stoichiometry.
I dont get why find the slope when the concentration here is constant in both graphs , or I just miss interpret this ? Help
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I dont get why find the slope when the concentration here is constant in both graphs
It is not. You use different amounts of substances to make the solutions, so the concentrations can't be constant.
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I dont get why find the slope when the concentration here is constant in both graphs
It is not. You use different amounts of substances to make the solutions, so the concentrations can't be constant.
OMG !! YOUR RIGHT! I didnt notice ! :D
but now I've plotted it, I had to use the linear correlation thingy and my slope ended having 3,108 ? why do you think so ...
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but now I've plotted it, I had to use the linear correlation thingy and my slope ended having 3,108 ? why do you think so ...
You can explain more, but you could also browse of forum for linear fit, there are several examples to choose from.
http://www.chemicalforums.com/index.php?topic=66862.msg240645;topicseen#msg240645
http://www.chemicalforums.com/index.php?topic=76035.0
http://www.chemicalforums.com/index.php?topic=65355.0
http://www.chemicalforums.com/index.php?topic=82575.msg299800;topicseen#msg299800
http://www.chemicalforums.com/index.php?topic=79489.msg289553;topicseen#msg289553