Saturday
December 7, 2013

# Posts by carrie

Total # Posts: 255

Chemistry
How do I calculate the amount of grams of Na2HPO4 and NaH2PO4 to prepare 200 mL of a buffer with an 8.25 pH so the sum of the concentrations of HPO4 and H2PO4 ions is 0.5 M? Does this involve writing a Ka expression and equilibrium? I am confused and Thanks for your help!

Chemistry
Sorry I don't know how it posted twice! Oops! :-)

Chemistry
How do I calculate the amount of grams of Na2HPO4 and NaH2PO4 to prepare 200 mL of a buffer with an 8.25 pH so the sum of the concentrations of HPO4 and H2PO4 ions is 0.5 M? Does this involve writing a Ka expression and equilibrium? I am confused and Thanks for your help!

chemistry
This is a verbatim question on my final review for 2nd quarter College General Chemistry and it didn't make any sense to me so that is why I decided to post and ask for assistance. You not knowing either doesn't make me feel any more confident in my ability to pass thi...

chemistry
How many grams of water are required to dissolve 27.8g of NH4(NO3)(MM=80.05 g/mol)to make a 0.500M solution?

Math
oh, ok thanks!

Math
Ok so you're supposed to solve the system by method of substitution. And the problem is: -2/3x + y = 2 2x - 3y = 6 So i put y= 2/3x into the second equation which looks like: 2x - 3(2/3x + 2) = 6 and then 2x-2x-6=6 So like everything cancels out? So then what do you put as...

Chemistry
If 25 grams of CoCl2•H2O,2 being the subscript of cl and the h, was heated to constant weight. What mass of anhydrous salt would remain?

literacy
When choosing your search strategy for a search engine, it's best to

Chemistry
This is a lab I have, but have no clue what to do. Please do out the steps so i can understand. Reactions and Data: NaOH(s)--> Na1+(aq)+ OH1-(aq) (Heat of solution of NaOH) This reaction involves adding solid NaOH to water and watching the temperature change as it dissolves...

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