CSte88

Why is this reaction carried out in an acidic solution? MnO4- + 8H+ + 5Fe2+ àMn2+ + 5Fe3+ + 4H2O Really appericate any help on this one, and sorry if its in the wrong place.

I know the rules for it, when I was 12 I learned them. Still, I think its odd how some people see a very simple question differently and get different answers.

Friend of mine showed me this last week and I though nothing of it, now I see its on facebook to day. To me all three answers look correct, but I'm sure that only one of them is (the second one). 6÷2(1+2) = 6÷2(3) = 3*3 = 9 or 6÷2(1+2) = 6÷2(3) = 6÷6 = 1 or 6÷2(1+2) = 6÷2+4 = 3+4 = 7 Anyone any ideas?

In a vacuum does light not play a part in effecting the electron? Or is the vacuum completely void of light and air? Should have mentioned this was the part I was having particular difficulty with. I vaguely remember being told light can have an affect, but really cant remember exactly what effect if any.

"Conduction of electrons through a vacuum". Explain.... I'm only looking for about a paragraph to fit in to an atomic physics assignment for college nothing too fancy. As physics is probably my weakest subject all and any help is greatly welcome!