CHEM 111 Lecture Notes - Lecture 12: Oxidation State, Chromate And Dichromate, Lead

• School: UMASS-Amherst
• Department: Chemistry
• Course: CHEM 111
• Professor: Julian Tyson

Document Summary

Chem111 lecture 12 oxidation and reduction reactions. You can write ch3cooh as hac and you can write ch3coo as ac. 2- + h+ co2 + cr3+ + h2o. Two chromium atoms go from +6 to +3 = 6: need to make these equal, thus, 3 c2o4, now, balance the o. 19 on the left, so need 7 h2o and hence 14 h: 3 c2o4. 2- + 14 h+ 6 co2 + 2 cr3+ + 7 h2o. 2- + h+ 6 co2 + cr3+ + h2o. 2- + cr2o7: check charges: lhs +6; rhs +6. As: on left is +3; on right is +5 (oxidation) Mn: on left is +7; on right is +2 (reduction) H: on left is +1; on right is +1; neither (same for o) To balance the expression, we make the electron loss equal to the electron gain (and then fix the numbers of atoms not involved in the redox process)