Question

(Cr2O7)2- + 2Al + 14H+ <—> 2Cr3+ + 2Al3++ 7H2O

1) how many ml of solution 1.50 M e (Cr2O7)2- are needed to act without residue with 0.8 grams of Al?

2) what is the concentration of the solution (Cr2O7)2-

Answer 1

Hmm, chemistry is hard! Does anybody have the answer? :/ I'm better with math

Answer 2

how many moles of Al in 0.8g? Say, x.
You will need half that many moles of Cr2O7 -- x/2
x/2 moles * 1L/1.5moles * 1000mL/L = ____ mL

Answer 3

I posted a qestion to you yesterday asking what 1.5 M e meant. No answer from you. I see you're still posting the error. This is a redox equation and the first thing you must do is balance the equation.