.

[andrewloppol]

.

[fady_22]

Yep, you can put proteins through electrophoresis, but you must put them in either an acidic or basic solution to give them a charge so that they can migrate to the pole with opposite charge during electrophoresis.

[stonecold]

Yep, you can put proteins through electrophoresis, but you must put them in either an acidic or basic solution to give them a charge so that they can migrate to the pole with opposite charge during electrophoresis.

Yeah, this was on STAV 08.  Good question.

[Martoman]

Cr's oxidation number is as

 

[kenhung123]

Yep, you can put proteins through electrophoresis, but you must put them in either an acidic or basic solution to give them a charge so that they can migrate to the pole with opposite charge during electrophoresis.

Can it be any charge or must be negative? If its positive how can it migrate to positive electrode?

[Martoman]

It is repelled by the positive electrode if its positive to go to the negative electrode.

It can be any charge.

[stonecold]

Since when can you have an oxidation number than is not an integer?

There were people who said they laughed when TSFX said in one of their exams that the oxidation number of nitrogen was 1/3.

[kenhung123]

I think its possible because oxidation numbers have no actual meaning...

[stonecold]

If that's the case, then I wish damn textbook companies would put it in their bloody books!

[Martoman]

You can IIRC

[Martoman]

2-methylpropanol + 2-methylpropanoic acid ----(conc. H₂SO₄)---> XXXXXX
Is it soluble or insoluble in water? I said insoluble, solutions to chemology 2010 say soluble though.. why ?

I don't know why they would say this. It is sufficiently big to mean that it is relatively insoluble.

[kenhung123]

I agree that its insoluble because dispersion forces are way stronger than the hydrogen bonds in such a big molecule

[fady_22]

And there's really nothing hydrophillic about it? The (=O) only?

Yes, but don't forget the side groups. These make the molecules harder to pack close together, and so the relative strength of the dispersion forces are low. Hence, probably soluble.

[fady_22]

I think just dividing the number of mole by the coefficient and stating that one reactant is the limiting is enough. You really can't do anything else.

[Mao]

Since you've all got one - I'll post my Q's here:

Cr₂O₂^-... oxidation number of Chromium here and why? Solution says +3.

It is as Martoman has said, 3/2. Oxidation numbers don't have to be whole numbers.

2-methylpropanol + 2-methylpropanoic acid ----(conc. H₂SO₄)---> XXXXXX
Is it soluble or insoluble in water? I said insoluble, solutions to chemology 2010 say soluble though.. why ?

I would also say it's insoluble (or poorly soluble). The resulting ester is has 8 carbons with an ester bond. Solubility is poor with C5 esters, let alone C8. Bad question imo.