The Periodic Table

« first day (2308 days earlier) ← previous day next day → last day (2376 days later) »

gateprep

06:01

Tell me something ..Why is Bravias Lattices and all so important mathematically.I can contruct my own lattices and that could be a possible combination..I have found this question on stackexchange but I could not find out anything..Pls help me about the same.

gateprep

06:36

If x and y are properties of the system and P(x,y) = Mdx + Ndy, where M and N are
functions of x and y, then for P to be a property of the system, the following criterion needs
to be satisfied.

∂M
∂y =
∂N
∂x

why is that so? Pls explain

gateprep

06:50

A spherical balloon of diameter 0.5 m contains a gas at 1 bar and 300 K. The gas is heated and the balloon is allowed to expand. The pressure in the balloon is found to vary linearly with diameter. What would be the work done by the gas when the pressure inside reaches 4 bar?

Now I have reached upto this

Pressure varies linearly with diameter
That means P α D
Or, P/D = constant
At 1 bar (105 Pa), Diameter, D = 0.5m
Thus the constant is 105

/0.5 = 2 × 105

Using the value of this constant, we can calculate the value of final diameter when P = 4 × 105
. Thus

we have initial and final diameter.
Now,
Work done =
∫ P. dV
Vfinal
Vinitial

= ∫ (2 × 105D). d (
Π
6
D
3) =

Dfinal
Dinitial

∫ (2 × 105D).
Π
6
3D
2 d(D
3)

somehow I am not able to arrive at the correct answer but my integral process was right I believe could someone come up with the techniques and help me arrive at the answer?

2 hours later…

Martin - マーチン

08:50

I wonder if I should put the trans in quotation marks, after all, the compound is not trans... Re: Regioselectivity of bromination of alkenes

6 hours later…

paracetamol

14:29

@AvnishKabaj What does it matter, so long as it tastes delish O:)

orthocresol

15:13

@Martin-マーチン i think it's ok, as trans describes the relative positions of the two Br in the initial conformation of the product, if that makes any sense

sometimes people talk about trans-diaxial addition (en.wikipedia.org/wiki/F%C3%BCrst-Plattner_Rule) even though the product might be trans-diequatorial

in any case the context makes it clear (imo)

Martin - マーチン

yeah, that's what I thought when I wrote it, I just realised that it doesn't really make sense because of the single bond...

thanks, I'm a bit puzzled, whether or not I should expand on the orbital thing...

orthocresol

Maybe 'anti' is a slightly better descriptor of conformation than 'trans', i.e. the two bromine atoms are anti to each other, but i think it's alright.

Martin - マーチン

I have no clayden and cannot look up how it's described in the epoxide section, like you suggested. I thought the whole part of the carbo-cation covers it alright...

I'll keep that in mind, if I decide to add anything

orthocresol

I like what you did, as I said I think its pretty convincing, even though its not the way that I was taught it.

Martin - マーチン

15:54

actually you once pointed something out that stuck with me (very end of Are compounds containing active methylene groups positive for the haloform test?), and even though alkyl moieties are much less of a factor, the principle should be in the same ballpark, that's why i chose this approach

4 hours later…