ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: Widdy on May 11, 2011, 08:50:09 pm
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Hey everyone,
I'm stuck for chemistry and the midyear exam is in 4 weeks. So for the people who's doing chemistry.
I need some notes for volumetric analysis, since my teacher is not the greatest teacher.
I can do the no.of moles, I just don't get back titration, and I don't get it when a question ask questions such as:
"What's the possible errors in this analysis?"
"Why is the result lower than the manafacturer's claim?"
"Will the result be higher if the clonical flask is washed with water/the primary standartd, etc.?"
So yeah, guys, thanks heaps if you can help with anything!
:) happy studying everyone!
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Check through this link:
http://vce.atarnotes.com/notes/index.php?step=download&search=&subject=Chemistry&units=MyY0
There are definitely some.
Errors in analysis can include
-Washing things with the wrong liquid
-Not drying things adequately
-Weighing errors
-Overshooting titre
-The contents of whatever we're measuring not being evenly spread out in the solution (hence a sample taken from it may be an inaccurate representation)
-Exposing certain chemicals to the atmosphere and them ending up increasing in mass due to atmospheric H2O
-Filter not done properly
-Chemicals that we didn't consider ending up reacting and causing products
There are heaps more, but those are a couple off the top of my head. There are quite a few of these available in notes. These would also lead to manufacturer's claims being off the experimental result.
For the final bit, just think about whether or not diluting (washing with water) effects your end result, and whether or not adding volume (washing with the said chemical) will alter your result.
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thanks!!