Chemistry Unit 2 Edexcel, Exam- 23rd May 2012

for N₂O₄(g) <=> 2NO₂(g)
why compressing the gases cause the mixture to darken.
NP: N₂O₄ pale yellow and NO₂ dark brown

I need helP

The oxidation number of oxygen is always -2 apart from in H2O2

So in H202 is it -1??

What does it mean by sealed apparatus guys? Surely if you weren't refluxing with sealed apparatus you'd lose volatile gases?

do you also pu that the solution turns brown (with KBr)

& the solution also turn black with KI ??

thanks

its thermal stability increases if polarising power decreases.
and the polarising power of group 1 is much less than that of group 2 as they have large ionic radius and smaller charge on ion than the ion of group 2 so the thermal stability of group 1 is more than that of group 2

no for reflux the apparatus is open at top while for distillation its open at the end. So for using ammonia you need sealed apparatus as you are heating in reflux. The ammonia will escape coz it cannot be condensed by condenser so you have to seal it.

VDW<Perm. dip. Perm. Dip < Hydro. Bond?? right LOL - just to clarify haha

Well something compressed tells me that the answer is something along the lines of the molecules are packed closer together?



It is -1 yes.

Ohhhhh, thank you!

I swear to god I am going to thermally decompose in a minute... it's too hot!

Thanks a lot dude, but are group 1 compounds always thermally stable than group 2 compounds ?

I swear to god I am going to thermally decompose in a minute... it's too hot!

thats a bit confusing. if compressed means volume decreased which means pressure rises since the number of molecule is more at right so position of equilibrium shift to left I don't know why would that be more darker? Its one of the question from the past paper.

I won't because I'm a group 1 carbonate, I'm thermally stable!


See whut I did tharr

no for reflux the apparatus is open at top while for distillation its open at the end. So for using ammonia you need sealed apparatus as you are heating in reflux. The ammonia will escape coz it cannot be condensed by condenser so you have to seal it.

Not if you're lithium carbonate

Forming an oxide? Uh oh!



Confused.com - Google to the rescue!

I thought they say sealed apparatus because it has to react under high pressure?

Guys, quick question. You know in the very latest past paper(2012) There was a question about titration and colour of solution just before you add starch. WHY THE HELL THE COLOUR IS PALE YELLOW ??

I thought Iodine in water is brown solution, and in hexane is purple. So why it is yellow?