Chromium is reduced from CrO4{2-} to Cr(OH)4- in an electrolytic cell. What mass of Cr(OH)4- is formed by passage of 4.50 A for a period of 8000 seconds?

Answer 1

Isn't an amp a coulomb of electrons?

number electrons=1coulomb/charge on each electron

Now, after you figure that out, multiply it by 4.5*8000 to get the number of electrons.

Thence, divide it by avagradros number to convert it to moles of electrons.

It appears the chronium went from +6 to +5, or each ion taking on one electron.
That number of moles of electrons is the same number of moles of CrO4 -2 ions, so what is the mass of that?