Posted by Adam on Friday, January 28, 2011 at 12:00am.
Could someone help me with these problems;
A)If 5.97mL of a solution of NaCl contains 2.54g of sodium ion, what is the molarity of the sodium chloride solution?
I know M=#moles solute/L
but when I do this I get 7.28*10^3 which is wrong, the answer should be 1.85*10^2
B) Combustion analysis of a 22.0mg sample of the painkiller morphine produced 13.2 mg of water. What is the % by mass of hydrogen in morphine?

Chemistry  DrBob222, Friday, January 28, 2011 at 12:15am
If you had shown your work I could have found your error; however, I suspect the error you made was to divide 2.54 g by molar mass NaCl (about 58.5) whereas the problem states that it is 2.54 g of the Na^+. So 2.54/23 = moles NaCl.
There is a bigger problem than that. Could you have made a typo and the 2.54 g whould be 2.54 mg? If so then
2.54 mg/23 = ?? mmoles and ??mmoles/5.97 mL = 0.0185 M.
But if 2.54g is correct, then
2.54/23 = 0.110 moles and that divided by 0.00597 L = a number 100 x higher than the answer. Of course, that could be 5.97L too for the correct answer to be 0.0185M
Answer This Question
Related Questions
 chemistry  an aqueous solution solution of sodium borate is sometimes used to ...
 chemistry  1. 15.0 g of sodium sulfate are dissolved in water to form 400.0 g ...
 CHEMISTRY  You have been given a sample of unknown molarity. Calculate the ...
 Chemistry  1. You have been given a sample of unknown molarity. Calculate the ...
 science  Q4.you will be asked to prepare 25.0 mL of a 0.019 M solution of ...
 CHEMISTRY URGENT  1. You have been given a sample of unknown molarity. ...
 chemistry  need help with these problems: The concentration of glucose in blood...
 chemistry  ihave two solutions. in the first solution , 1.0 moles of sodium ...
 Chemistry  An aqueous solution is 8.50% ammonium chloride, NH4Cl, by mass. The ...
 College Chemistry  In this lab: we demonstrated the method of evaporation of a ...
More Related Questions