[carfreak95]

I'd appreciate it if someone could step by step answer this question and explain tricky parts please
i have a test soon and this may be one of the harder questions.

Clearly outline a procedure for making the following aqueous solution by diluting a stock solution:  150 mL of 0.300M ammonia, using 6.0 mol/L ammonia."

Your solution should indicate that you should add 7.5 mL of a 6M ammonia solution, adding water until you reach the 150 mL mark.  This would give you a 0.300 M solution.

CHALLENGE:
OOPSS!!  Instead of adding 7.5 mL, you only added 5.0 mL of the 6M ammonia solution.  WHAT COULD YOU DO (outline a detailed procedure) to CORRECT the situation.  This means, you want to save the flask of diluted solution and not to have to dump everything out and start from scratch!

I want the final concentration to be 0.300M.  (Hint:  the final volume of the flask would be greater than 150 mL)

EXTENSION:
Now, a new criteria is that I must use whole number concentrations as those are the ones available in stock bottles.  That means, stock bottles would be 1M, 2M, 3M, 4M, etc.. up to 10M.  Develop a recipe to change the concentration of the existing flask.

[Schrödinger]

Please read forum rules. Did you attempt to solve the question?

[carfreak95]

Yes, I did. The first part is simple and I solved it with C1V1=C2V2
But I don't understand how to fix it if you put in the wrong amount. Can someone please help me? I really need to understand this. I have a feeling variables might be needed but I'm not sure how to do this.
Thanks