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Rtael
Sep 15th, 2004, 01:16 AM
Okay I need some help....I'm doing my homework and I have this redux reaction where I am given Cr + NiSO(4) and I have to give what it yields, based on the activity series. What I'm confused about is which ion of Cr I'm supposed to use? It has a variable charge and I have no idea which charge to use....it doesn't say anything else in the problem. I asked my teacher during class but she just ignored me. :rolleyes:

Carolina Girl
Sep 15th, 2004, 01:32 AM
I asked my teacher during class but she just ignored me. :rolleyes::rolls: sounds like my chemistry teacher

i swear every day i walk out of that classroom with a headache!

Well, I'm sorry to say I can't help you:p

We haven't gotten that far yet so alas I am no help to you

Rtael
Sep 15th, 2004, 01:39 AM
:p

Carolina Girl
Sep 15th, 2004, 01:51 AM
:pyou think i'm kidding:p she even confuses herselfs sometimes:p

It's like teaching yourself in her class.

Rtael
Sep 15th, 2004, 01:54 AM
Okay nevermind....pretty sure I understand now...anyway I know how you feel Zelda...that was my teacher last year, which is why I don't understand anything this year!

treiber04
Sep 15th, 2004, 01:56 AM
:tape: Oh my god you're asking for help on your homework on a Tennis Chatboard? :haha: Don't you have friends you can ask? OR YOUR PARENTS?

Carolina Girl
Sep 15th, 2004, 01:58 AM
Okay nevermind....pretty sure I understand now...anyway I know how you feel Zelda...that was my teacher last year, which is why I don't understand anything this year!well i'm glad you figured it out.

Yes, I have a feeling this year is going to suck, but I can't really complain that much right now i have a 99.1 % average in there, so it ain't too bad:p

I guess I am just a good teacher?:p

Rtael
Sep 15th, 2004, 02:48 AM
:tape: Oh my god you're asking for help on your homework on a Tennis Chatboard? :haha: Don't you have friends you can ask? OR YOUR PARENTS?

Well I know which people I wouldn't trust answers from. Namely, you.

bw2082
Sep 15th, 2004, 03:23 AM
Cr + NISO4

Cr + NiSO4(aq) ----> CrSO4(aq) +Ni
Cr + Ni^+2(aq) + SO4^-2(aq) -----> Cr^+2(aq) +SO4^-2(aq) +Ni
Cr + Ni^+2 (aq) -----> Cr^+2 (aq) +Ni

Cr has to be a +2 charge to pair up with the sulfate

Ameliepatriote
Sep 15th, 2004, 03:41 AM
Take Away the Nickel, It's only a spectator Ion, Much like The Potassium in Potassium Permenganate K(MnO4) # -2 (The Charge)

That should leave with you with the Dichromate Ion (Cr2O7 #2-) which will reduce to The Chromate Ion (Cr 3+ )

The Half Equations from what you have should read.... Cr207 2- + 14 H + 6e- ----> 2Cr3+ 7H20

SO4 from your Nicol Sulfate is an oxidising agent, and so is your Dichromate....hmmmm One needs to be a Reducing Agent....You cant have the same charges on the same side.... Sure it wasn't Sulphur Dioxide or SO3 2- ???? that was linked to the Spectator Ion???

Ameliepatriote
Sep 15th, 2004, 03:53 AM
Cr + NISO4

Cr + NiSO4(aq) ----> CrSO4(aq) +Ni
Cr + Ni^+2(aq) + SO4^-2(aq) -----> Cr^+2(aq) +SO4^-2(aq) +Ni
Cr + Ni^+2 (aq) -----> Cr^+2 (aq) +Ni

Cr has to be a +2 charge to pair up with the sulfate

It's Redox Reactions and the usage of Ion electron equations..........cr ---> cr 3+ and so4 2- should oxdised to s. But they are both reducing Agents, One needs to be oxidised,

Cr3+ + e- Cr2+ - 0.408

But thats rare in Redox, and If your doing basic Redox, it is surley not in your sylabus,

Cr2O72- + 14H+ + 6e- 2Cr3+ + 7H2O thats the basic half equation you need to know,

selking
Sep 15th, 2004, 04:01 AM
i f-ing hate chem

skanky~skanketta
Sep 15th, 2004, 08:27 AM
OMG!i'm getting some nasty flashbacks.

girlfriend, i may have gotten a C for my chem A-levels, but that was cuz i gave a good lapdance. and even with a lapdance i still got a C. which tells u how bad it was.