[remeday86]

 0.775 mmol iron(III) nitrate =  0.3131 g iron(III) nitrate


I don't understand why I have this wrong on WileyPlus. Also, I tried punching in 0.313 g but that also didnt work.

0.775 mmol Fe(NO3)3*9H2O x ( 1 mol Fe(NO3)3*9H2O/ 1000 mmol Fe(NO3)3*9H2O) x ( 403.9981 gFe(NO3)3*9H2O  /1 mol Fe(NO3)3*9H2O) = 0.3130985....

 

[sjb]

I would assume, that you are not using the correct formula for iron(III) nitrate.

Look at what it is you are calculating the molecular mass for.