Wednesday, December 1, 2010
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Thursday, May 21, 2009
That brings us to stoichiometry. Stoichiometry is the study of relationships in chemical reactions. in other words, it's the study of what amounts of things are equal to amounts of other things in chemical reactions.
Monday, May 11, 2009
How do you balance redox reactions? Why do questions about balancing redox reactions tell me whether the solution is acidic or basic?
Saturday, March 21, 2009
Interactive periodic table courtesy Sapling Learning. This periodic table is licensed under a Creative Commons Attribution 3.0 United States License, and is free to use so long as you credit and link to Sapling Learning. A larger version is available here.
Thursday, February 19, 2009
I'm working on a question where I have to find the concentration of CaCO3 in ppm using information from EDTA titration. What is ppm? How can I find it?
The formula for the complex ion formed by EDTA is M[EDTA]2+, where M could be Mg or Ca. Since there is a 1:1 ratio of EDTA and metal ion, the amount of EDTA you needed to reach the end point of the titration equals the amount of metal ions in solution.
You can find the concentration of CaCO3 a couple of different ways.
- conc. CaCO3 = (conc. EDTA)(vol. EDTA)/(vol. water) remember to keep track of units!
- find the moles of EDTA, which equals the moles of CaCO3, and then divide by the volume of water to get the concentration of CaCO3.
% - (mass of part)/(mass of whole) *100
ppm - (mass of part)/(mass of whole) *1,000,000
Wednesday, February 18, 2009
What is density? How can I calculate the density of a sample?