AQA - Unit 5 - Energetics, Redox and Inorganic Chemistry

I'm gonna go over random bits of revision guys:

Cr2+ can be [O] to Cr3+ by reducing Cr2O7^2- by zinc in acid sol.
H2 can be used to exclude air
Then the equations:
Cr2O7^2- is [R] to Cr3+
Zn is [O] to Zn2+

I heard the unit 4 June paper was tough so bit worried about this one, very worried. :cry2:

Reply 501

GoodOl'CharlieB

Original post by Sparkly-Star

Me too!

Ugh, the annoying thing is I should've gotten an A in unit 4 but I completely blanked out there was so much to learn and this was my last exam in Jan by then I had forgotten everything despite spending countless hours on it. -_- So I need to do extra well in this unit. :mad2:

I have to say that I love this smilie :mad2:

... it sums up my ranting and raving about AQA every exam period, especially about shrew papers in Biology lol

I'm reaching the end of my first chapter, so I'm making steady progress. I started with Chapter 16 first because its got so many equations and colours :sigh:

Lets hope AQA are nice so that we can ace the exam but not too nice that the grade boundaries go up :biggrin:

Reply 502

Sparkly-Star

13

Original post by strawberry_cake

I hate it when that happens, especially if its easy marks, that really puts me off :frown:

I just can't wait for tomorrow to be over, although I wouldn't have minded an extra day or two :s-smilie:

Give me another week haha. :colondollar:

Reply 503

lfc4lyf

5

so going to fail
last exam so staying up all the way till the exam tomorrow !!!
oh god please help me!!

Reply 504

strawberry_cake

Can someone please tell me 4a for feb2010 paper? I don't know how its 242? Thanks :smile:

Reply 505

Sparkly-Star

13

Original post by GoodOl'CharlieB

I have to say that I love this smilie :mad2:

... it sums up my ranting and raving about AQA every exam period, especially about shrew papers in Biology lol

I'm reaching the end of my first chapter, so I'm making steady progress. I started with Chapter 16 first because its got so many equations and colours :sigh:

Lets hope AQA are nice so that we can ace the exam but not too nice that the grade boundaries go up :biggrin:

Me too

I started with 15 for the same reason, I find 16 easier. Luckily I had to do tons of revision on chapter 15/16 for my ISA so I don't find them too bad.
Yeah I don't think the difficulty will change a lot, the grade boundaries seem to stay around the same numbers. :yep:

Hmm on another note, where are all the chem people? The bio thread was full!

(edited 12 years ago)

Reply 506

GoodOl'CharlieB

Original post by strawberry_cake

I hate it when that happens, especially if its easy marks, that really puts me off :frown:

I just can't wait for tomorrow to be over, although I wouldn't have minded an extra day or two :s-smilie:

What is keeping me revising is thought of freedom at 10:45 tomorrow, as soon as I hand in that paper its going to be one big party :party:

I just keep thinking of all the fun things I've planned this summer and about getting into uni...otherwise I probably would have gone insane :crazy:

We can do this!! :biggrin:

Reply 507

al_habib

1

Original post by ceeebs

got about 3 left coz bio revision came in the way

woow! thats hard core revision, am on 2006 now hope to finish by this afternoon the rest.

Reply 508

Sparkly-Star

13

Original post by strawberry_cake

Can someone please tell me 4a for feb2010 paper? I don't know how its 242? Thanks :smile:

Cos it's twice the atomization of the first one in the table from the top of my head. :yep:

Reply 509

strawberry_cake

Original post by Sparkly-Star

Cos it's twice the atomization of the first one in the table from the top of my head. :yep:

Ohh but then for 4dii) why don't we double the values for Cl? And thanks :biggrin:

Reply 510

Sparkly-Star

13

Almost done with chapter 15. :jive:

Longest chapter of all damn it. :p:

Reply 511

Sparkly-Star

13

Original post by strawberry_cake

Ohh but then for 4dii) why don't we double the values for Cl? And thanks :biggrin:

Cos we're forming AgCl which contains only 1 Cl- :smile:

Reply 512

Casshern1456

18

Do anyone feel like they don't have enough time :s-smilie:

I'm so screwed for tomorrow!

Reply 513

Crowned Temmy

7

Help me!!! I am confused about lattice enthalpy. Is -1025KJ/mol greater or lesser than -998KJ/mol. Mathematically, -1025 is lesser, but I don't know why me book is confusing me. Could you also explain the trend in lattice enthalpy of formation (based on ion size and charge) and electron affinity down the group?

Reply 514

Luke0011

11

Am I the only person who doesn't have study leave?
I've got to go into college still today!

Good luck for tomorrow everyone!

What is everyone learning for the synoptic stuff?
I dont have any of the previous books because we have to hand them in :frown:

Anyone want to give me a quick overview? Would be amazing haha :wink:

Thanks!

Reply 515

Sparkly-Star

13

Has everyone memorized 15.4/15.5? :colondollar:

Reply 516

Luke0011

11

Original post by Crowned Temmy

Help me!!! I am confused about lattice enthalpy. Is -1025KJ/mol greater or lesser than -998KJ/mol. Mathematically, -1025 is lesser, but I don't know why me book is confusing me. Could you also explain the trend in lattice enthalpy of formation (based on ion size and charge) and electron affinity down the group?

Probably easier if you say it is more negative. So more energy is needed to break the bonds within the lattice.

Across the period, ion size decreases because nuclear charge increases, and attracts the electrons more, so atomic radius decreases. This means that there is a higher charge:size ratio, so attracts the other ions in the ionic lattice more. Al2O3 also has a degree of covalent bonding, so its experimental value will be higher than that calculated in the perfect ionic model.

But SiO2 makes a macromolecular lattice, held by covalent bonding, so lots of energy needed to break strong covalent bonds.

P4O10 onwards, simple molecular structures, so weak intermolecular forces.

The lattice formation is just the -ve of the lattice dissociation, so you can use that to find the trend :smile:

Not sure about electron affinity down the group though, sorry!

Reply 517

Sparkly-Star

13

Original post by Crowned Temmy

Help me!!! I am confused about lattice enthalpy. Is -1025KJ/mol greater or lesser than -998KJ/mol. Mathematically, -1025 is lesser, but I don't know why me book is confusing me. Could you also explain the trend in lattice enthalpy of formation (based on ion size and charge) and electron affinity down the group?

From the top of my head, it is less mathematically BUT think of it as fireworks which is exo. If you had fireworks and had one of them sparkly things it might be -998 which is small but if you had one of those big fireworks in the air (whatever they're called :colondollar:

) those are greater -1025 hence it is MORE exo.

Lattice enthalpy increases as the size of the ions decreases this is because the ions are more attracted I think.

Electron affinity, not sure.

(edited 12 years ago)

Reply 518

Thisisj

hi, can someone please help me with thermodynamics... it will help you revise too :smile:

i understand the terms and stuff but it's not too clear.. any help on the wholeeeeeeee topic will be sooooo much appreciated .. thanks :smile:

Reply 519

Sparkly-Star

13

Original post by Luke0011

Am I the only person who doesn't have study leave?
I've got to go into college still today!

Good luck for tomorrow everyone!

What is everyone learning for the synoptic stuff?
I dont have any of the previous books because we have to hand them in :frown:

Anyone want to give me a quick overview? Would be amazing haha :wink:

Thanks!

I doubt anything from unit 4 will come up maybe bits and bobs from unit 1/2 so things like percentage yield and so on, energetics, extraction of metals maybe.

AQA - Unit 5 - Energetics, Redox and Inorganic Chemistry

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you