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February 12, 2016

# Homework Help: Chemistry -- to Dr.Bob

Posted by James on Thursday, April 24, 2008 at 8:53pm.

i put 1 for the spaces before both of the Fes and got them both wrong but i got the others right. thank you

Balance the equation:
Note: If a chemical species coefficient is "1" then "1" needs to be entered in the field before that species.

1 MnO4– + 8H+ +__ Fe2+ -->1Mn2+ + 4H2O + __Fe3+
• Chemistry -- to Dr.Bob - kelly, Thursday, April 24, 2008 at 9:30pm

put 6 before Fe2+ and Fe3+

• Chemistry -- to Dr.Bob - James, Thursday, April 24, 2008 at 10:54pm

wait why is it 6?

• Chemistry -- to Dr.Bob - kelly, Thursday, April 24, 2008 at 11:43pm

because its a redox reaction. the number of electrons in the Fe2+ to Fe3+ half-equation must equal the number of electrons in the MnO4 to Mn2+ half-equation, which is 6. Thus you need to have 6 Fe2+ and 6 Fe3+ also.

Balance each half-equation first, and then combine the 2. :)

• Chemistry -- to Dr.Bob - DrBob222, Thursday, April 24, 2008 at 11:40pm

Mn changes from +7 on the left to +2 on the right.
Fe changes from +2 on the left to +3 on the right.
Therefore, place a 5 for both Fe on the left and right. The others are ok.

• Chemistry -- to Dr.Bob - UCI kid, Monday, April 28, 2008 at 5:10pm

don't put 6. it's wrong in webwork

• Chemistry -- to Dr.Bob - Aly, Monday, April 27, 2009 at 3:19pm

Put 5 before Fe2+ and before Fe3+