Question

Which of the following are oxidation half-reactions?

Cr2O72- → Cr3+

MnO4- → MnO2

Fe2+ → Fe3+

Cl- → Cl2

Answer 1

@anitasonia98 would you mind helping me w a few more questions?? sorry i keep tagging you im just new and you have been the most helpful!

Answer 2

It's ok!
Oxidation means that you're losing electrons :)
So which choice would it be?

Answer 3

@anitasonia98 would it be choice B?

Answer 4

In choice B, Mn is gaining electrons (it has a charge of +7 in MnO4-, and then it has a charge of +4 in MnO2).

Answer 5

When you lose electrons, the positive number becomes larger. :)

Answer 6

so its C?!

Answer 7

@anitasonia98 could it be C and D?

Answer 8

C is it :)

Answer 9

Wait, hold on

Answer 10

It's C. :)
A different reaction is going on in D, I think.

Answer 11

@anitasonia98 okay thanks! i have like 2 or 3 more questions i need help with is that cool?

Answer 12

Np! And that's fine :)

Answer 13

@anitasonia98

1.) H2O and OH- are added as needed to the half-reaction equations to make the number of oxygen and hydrogen atoms balance.

Divide the chemical equation into two half-reaction equations, identifying which half-reaction is oxidation and which is reduction.

H2O and H+ are added as needed to the half-reaction equations to make the number of oxygen and hydrogen atoms balance.

Multiply each term in one of the half-reaction equations by a factor that will make the number of electrons lost (in the oxidation) equal to the number of electrons gained (in the reduction).

2.) Consider the following unbalanced redox reaction:

I2 → IO3-

How many water molecules are needed for balancing?

3 on the reactant side

3 on the product side

2 on the product side

2 on the reactant side

3.) Which of the following is a use for electrolytic cells?

electroplating

rechargeable batteries

car batteries

watch battery

Answer 14

I haven't done redox reactions in a long time :o
As for #3, it would be rechargeable batteries :3

Answer 15

I've kinda forgotten how to do redox, whoops.
http://www.shodor.org/unchem/advanced/redox/

Answer 16

@anitasonia98 thank you! :)

Answer 17

Sorry about not being able to answer #1 and #2 :o I haven't done those in such a long time.

Answer 18

http://www.cabrillo.edu/~aromero/CHEM_1A/1A_Handouts/Balancing%20Redox%20Reactions.pdf

Answer 19

That seems to be a slightly better explanation for how to figureout redox :o

Answer 20

figure out*