A chemist wants to make 150 mL of a 1.26 M solution of carbonic acid to be used in the lab. How many grams of H2CO3 does the chemist need to make this solution? I converted mL to .150L, multiplied .150*1.26= =0.189 to get mol. H2CO3=62.028 so I multiplied this by 0.189 to get grams.. I got 11.722 but it's incorrect

2 answers

I expect you are reporting too many significant figures. You're allowed just three; therefore, I would round the answer to 11.7 g. By the way, you will have some trouble making 1.26 M solution of H2CO3. A saturated solution isn't that strong.
I put 11.7 and it still marked me wrong :(