Gchem

[Glycogen]

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Anyone can explain this please?
BTW,I do have the answer, I just don't understand the concept.
Thanks.

1) Copper is electroplated from CuSO4 solution.A constant current of 10.00 amps is applied by an external power supply for exactly 75 minutes.How many grams of copper can be plated out during time interval?The atomic mass of copper is 63.55.

2)Which of the following solid salts should be more soluble in 1 M NH3 than in water?

a.Na2CO3
b.KCl
c.AgBr
d.KNO3
e.NaBr

 

[TeamGuo]

Anyone can explain this please?
BTW,I do have the answer, I just don't understand the concept.
Thanks.

Copper is electroplated from CuSO4 solution.A constant current of 10.00 amps is applied by an external power supply for exactly 75 minutes.How many grams of copper can be plated out during time interval?The atomic mass of copper is 63.55.

This is dealing with electrolysis. First you would have to know the half reaction of CuSO4

Cu2+ + 2e- --> Cu , so we are transferring 2 electrons to get to Cu zero.

Now it's just dimensional analysis.Note amp = Coulombs/s

(10.00 C/s)(6500 s)(1 mol e-/96500 C)(1 mol Cu/2 mol e-)(63.55 g/mol)

That's the setup. Hopefully I didn't forget anything, too lazy to do the calculation which I doubt they ask us to find out the numerical value on the DAT.

If you having trouble with this, just use this formula, which should do the job.


(amp)(ts)(MW) / 👎(F) = grams of product

amp = C/s
ts = time in seconds
MW = molecular weight
n = number of moles of electrons
F = Faraday's constant = 96000 C/1mol e-

 

[Danny289]

Anyone can explain this please?
BTW,I do have the answer, I just don't understand the concept.
Thanks.

Copper is electroplated from CuSO4 solution.A constant current of 10.00 amps is applied by an external power supply for exactly 75 minutes.How many grams of copper can be plated out during time interval?The atomic mass of copper is 63.55.

You want to solve this problem or you want to know the concept? if you want to solve the problem you need more information but about the concept look at the attachment, and i am sure you have enogh data to solve it.
don't pay attention to the "pot" just see whats going on.
and for your second question I go for :
AgBr
and you will have Ag[NH3]2Br

 

[TeamGuo]

oh I didn't see number 2.

I must say it's AgBr, since Ag salts are usually nonsoluble.

AgBr + H2O --> AgOH which is non soluble, whereas, all of the other compounds with OH will be soluble, since they are group 1 metals.

So watch out for Ag, Pb, Hg, since those form insoluble salts

 

[PooyaH]

You want to solve this problem or you want to know the concept? if you want to solve the problem you need more information but about the concept look at the attachment, and i am sure you have enogh data to solve it.
don't pay attention to the "pot" just see whats going on.
and for your second question I go for :
AgBr
and you will have Ag[NH3]2Br

haha I like the pot in there Danny jan! 😀

 

[Danny289]

haha I like the pot in there Danny jan! 😀

Fadat pooyajan pot= "kaseeh mesi" 😀

 

[PooyaH]

Fadat pooyajan pot= "kaseeh mesi" 😀

lol yeah I got that 😀

 

[Glycogen]

You guys are Persian!!!!!!🙂
No wonder you are all here studying on 4th of July!!!!!!
From now on I will ask my Qs exclusively from my Persian SDNers!!!

 

[chitownsmiles]

on the real DAT wouldn't they give us faraday's constant, or do we need to memorize things like that?

 

[Danny289]

you Guys Are Persian!!!!!!🙂
No Wonder You Are All Here Studying On 4th Of July!!!!!!
From Now On I Will Ask My Qs Exclusively From My Persian Sdners!!!