[clw89]

I am having a lot of trouble with these problems. Any help for any of the following questions would be greatly appreciated. I have already attemted to do these several times and I can't seem to get the right answer! Thanks for all your *delete me*

1. When 11 mL of a solution containing 2.7 M AlBr3 is diluted to 33 mL, a dilute solution is formed. What is the Br- concentration in 15 mL of the dilute solution?

2.When 15 mL of a solution containing .31 M Ca(OH)2 is diluted to 30 mL, a dilute solution is formed. What is the OH- concentration in 15 mL of the dilute solution?

3. When 28 mL of a 330 mL stock solution containing 2.2 M AlCl3 is diluted to 103 mL, how many moles of Cl- are in the new solution?

4. 4. A stock solution is prepared by adding 23 mL of 1.9 M Na2SO4 to enough water to make 40 mL. How many moles of Na+ are in 15 mL of the stock solution?

5. 5. How many milliliters of a 150 mL solution of 2.1 M Na3PO4 must be used to make 69 mL of a solution that has a concentration of .6 M Na+?

6. A 11 mL sample of a solution of AlBr3 was diluted with water to 27 mL. A 15 mL sample of the dilute solution was found to contain 0.05 moles of Br-. What was the concentration of AlBr3 in the original undiluted solution?

Thanks!

[CT101]

Please post your attepmt at the problems so that we may see where you went wrong and steer you back in the right direction.