# Chemistry Molarity Q

i combined 5 mL of 0.20 M Fe with 1 mL of 4.0x10^-4 M HSCN and 4 mL of 0.5 M HNO3

i am asked to find the molarity of FeSCN.

i am given this statement: "The concentration of Fe is so high relative to that of HSCN that we can assume that all SCN present is in the complexed form, FeSCN. In other words, HSCN is the liming reagent and the number of moles of HSCN added equals the number of moles of FeSCN that forms."

so i calculated the moles of HSCN by multiplying the molarity by the amount added -> (4.0x10^-4)(0.001) = 4.0x10^-7
apparently this is the same as the moles of FeSCN.

how do i find the molarity of FeSCN? i know the moles, so all i need is the volume (Liters), but i dont know how much to use in the equation... any suggestions?

Thanks

## Answers and Replies

Borek
Mentor
You have mixed everything together, right? So what is the final volume of the mixture?

symbolipoint
Homework Helper
Education Advisor
Gold Member
A matter of simple accounting for total volume of the prepared solution of FeSCN. Sum of the volumes used in preparing the solution.

the total volume would be 10 mL

thanks guys, i got it from here (hopefully) :D