Question

Medals

Answer 1

Which of the following chemical reactions is an oxidation-reduction reaction?

WO3 + 3H2 yields W + 3H2O

KNO3 + LiCl yields LiNO3 + KCl

CaSO4 + 2NaCl yields Na2SO4 + CaCl2

Mg(NO3)2 + 2HBr yields MgBr2 + 2HNO3

Answer 2

@aaronq

Answer 3

oh man, do you know how to assign oxidation states?

Answer 4

no :(

Answer 5

it's easy, but kinda lengthy. But, most of the time it's easy to tell, when you have an element forming a compound, or compound breaking up into elements, its indicative of a redox reaction.

Answer 6

I wrote this for another question, hope it helps.

You start off with a basic set of rules and you figure the rest out with simple arithmetic.

Rules (most often true, except in rare occasions):
Group 1 always +1
Group 2 always +2
Oxygen always -2
Group 7 always -1
Noble gases, elemental or homonuclear (the same element) molecules are zero

The rest you have to figure out by subtracting or adding to achieve whatever charge the compound bears.

eg. H2O
H is group 1, so H = +1, there are 2 of them
O must balance the charge so, O=-2

HCl
H=+1, Cl=-1

MgSO4,
you have to know that SO4^2- is a polyatomic ion, treat that as it's own separate thing:
O=-2
Total contribution of O=-2(4) = -8
^4 oxygen atoms

Charge on ion=-2, so S has to fulfil the rest which is 6, so S=+6

back to MgSO4, so we treat SO4 as entity and it bears a -2 charge,
Mg therefore has to be +2 to balance the charges.

Answer 7

I can tell you the answer for this one if you want, unless you have more similar questions, if so, you should learn how to do it.

Answer 8

yes please lol

Answer 9

@aaronq

Answer 10

It's A
(+6)(-2) 0 0 (+1)(-2) <- oxidation states
WO3 + 3H2 yields W + 3H2O

W was reduced +6 to 0
H was oxidized 0 to +1

Answer 11

thx, could you give me a few more lol cuz I onlyhave a few more and on adeadline lol of 10 min