ok i need help on figuring this out any help?.

Question

anonymous · Answer

|dw:1381891152556:dw|
what mass of limestone must have dissolved if 3.05x10^10kg of calcium hydrogen carbonate was produced?

aaronq · Answer

You first need to convert the mass given to moles, then build a ratio, like so:

e.g. for a general reaction:

                      $\color{red}{a}A + \color{blue}{b}B$ $\rightleftharpoons$ $ \color{green}{c}C$

where upper case are the species (A,B,C), and lower case (a,b,c) are the coefficients,

                     $\dfrac{n_A}{\color{red}{a}}=\dfrac{n_B}{\color{blue}{b}}=\dfrac{n_C}{\color{green}{c}}$


so if you have moles of B= 2, how many moles of C did you produce?

solve algebraically:      $\dfrac{2}{\color{blue}{b}}=\dfrac{n_C}{\color{green}{c}}\rightarrow n_c=\dfrac{2*\color{green}{c}}{\color{blue}{b}}$

To convert mass to moles, use the relationship:

                             $n=\dfrac{m}{M}$

        where, M=molar mass, m=mass, and n= moles.

anonymous · Answer

thanks i finally got i believe i was confusing it a bit thank you :)