Destroyer 70

[osimsDDS]

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Hey so in the back of for the answers in destroyer for question 70 its driving me nuts i cant figure this out....

When they balance this equation they get thats its going from +6 -----> +3
I am fine with +6 but how did they get +3 on the right???

6e- + 14H+ + Cr2O7^2- ----> 2Cr^3+ + 7H20

Now obviously the oxidation of chromium on the left is +6, but on the right chromium is supposed to be +6 no??? you have a +3 charge and 2 moles of it...someone please explain this thanks...

 

[osimsDDS]

hahaah nvm i just answer my own question iam an idiot...its because you are comparing Cr with Cr not Cr with 2Cr....the Cr on the left is just 1 mole of Cr while the one on the left has to also be 1 mole of Cr so its just +3...you can also do 2x+3=+6 but then devide by 2 to get +3 cuz its JUST 1 molecule of Cr...my bad ppl thanks

 

[imeddie]

yeah, just 1 mole!