hey i'm in yr 12 chemistry in Australia and im having problems understanding redox reactions equations, i understand oxidation states and a little bit but i cant figure our about the electrons calculus, i can do the rest of the formula or steps but i cannot seem to be able to calculate the electron transfer accurately i was hoping some one would be able to help with methods or something.
thank you
Borek
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equation balancer and stoichiometry calculator (http://www.chembuddy.com/?left=EBAS&right=equation-balancing-stoichiometry)
koosney@stcc
Aug10-08, 02:38 AM
thanks but that doesn't really help me calculate how to balance electrons in half equations (thats the only problem i am having)
jaska22
Aug10-08, 08:07 AM
Hi,
I think I understand what you are having trouble with. When you are finished balancing a half-equation and lets say it looks like this:
Au3+(aq) + 2I−(aq) -> Au(s) + I2(s)
(3+ and - on left side are charges), so you have Au (3+) and I (2-) on left, and on right you dont have any charges as you can see. Notice that when you have a number in front like 2I, make sure you dont forget that number and see only one (-) at the top, you actually have (2-). So, now 2 out of 3 protons of Au on left will balance 2 electrons on left and you will be left with one proton (1+) on left. Then, if you want to balance electrons, you see that you have zero on right and you want same on left so you add one e- to the left to cancell the proton (+) you had left over after you balanced your equation. Same thing if you had in the end 4+ on left and 2- on right of equation you would add 6- to left to cancell 4+ and have 2- left over to balance the right side.