iGCSE 2012 Chemistry Discussion

Heey what's up with the calculations about Moles and Faradays/charge/electrons? And I don't understand electrolysis moles calculations...
In fact I don't understand electrolysis at all...
So how does that work?
Does anyone know? :smile:

I don't get ionic equations....
:frown:

Reply 601

duper123

any recommended helpful youtube videos like the benardryl user for physics?

Reply 602

RoyalBlue7

19

Original post by (◕ ‿ ▒r▀▀

You're wrong. Don't confuse people...little knowledge is dangerous...
1. It's lubrication is not a direct nor an indirect result of it having delocalised electrons.
2.It is a giant molecule that continues in 2D ie it layers are on one plane
3.It does contain intermolecular forces. Then what do you call the weaf forces between the layers? Van-de-wall forces? van-de-wall forces are also a type of intermolecular attractions!

Absolutely right

Reply 603

Relaxedexams

2

Original post by (◕ ‿ ▒r▀▀

What???
this is wrong! Stop confusing me!

What I meant was that there are NO intermolecular forces of attraction between molecules in graphite of the same layer. There are weak forces of attraction between the layers, hence its slippery property. But when you vaguely say that the inter molecular forces of attraction are weak, you can assume that intermolecular forces of attraction between molecules of the same layer are being talked about...

Reply 604

Big-Daddy

13

Original post by (◕ ‿ ▒r▀▀

You're wrong. Don't confuse people...little knowledge is dangerous...
1. It's lubrication is not a direct nor an indirect result of it having delocalised electrons.
2.It is a giant molecule that continues in 2D ie it layers are on one plane
3.It does contain intermolecular forces. Then what do you call the weaf forces between the layers? Van-de-wall forces? van-de-wall forces are also a type of intermolecular attractions!

It is an indirect result of the graphite having delocalized an electron per C atom, as it therefore does not form the 4 C-C bonds which are present in diamond, which is why there are merely intermolecular forces between the layers.

That's still misleading - atoms themselves are not 2D. Why not just say that graphite consists of layers?

Van der Waals forces are all intermolecular forces of attraction. But graphite cannot melt or evaporate into different layers simply through the breaking of its van der Waals forces; you'd also need to break the (much stronger) C-C covalent bonds within each layer, which requires a lot more energy.

Reply 605

▀▀▒=(◕ ‿ ◕)=▒r▀▀

Original post by Big-Daddy

That's still misleading - atoms themselves are not 2D. Why not just say that graphite consists of layers?

Van der Waals forces are all intermolecular forces of attraction. But graphite cannot melt or evaporate into different layers simply through the breaking of its van der Waals forces; you'd also need to break the (much stronger) C-C covalent bonds within each layer, which requires a lot more energy.

Thats what i posted in the previous page!

Original post by (◕ ‿ ▒r▀▀

Graphite is a giant covalent structure and is an allotrope of carbon. Unlike diamond it if formed in 2D layers and does contain weak intermolecular forces. But as it is a giant covalent structure to sublime it you not only need to bread the weak intermolecular forces but the covalent bonds as well..

Um mm, yes you're right about the inter-molecular forces occurring as a result of a lone electron.

Reply 606

▀▀▒=(◕ ‿ ◕)=▒r▀▀

I am a New Member. Just asking if you need or needn't go through all the previous posts before reading a new one. People just say this and that is misleading "out of the context"

Reply 607

▀▀▒=(◕ ‿ ◕)=▒r▀▀

Original post by Relaxedexams

What I meant was that there are NO intermolecular forces of attraction between molecules in graphite of the same layer.

No you didnt mean it. Read what you wrote below

Original post by Relaxedexams

There arent intermolecular attractions in graphite. Graphite is a giant covalant substance. It doesn't have intermolecular forces.

But NOW you mean IT

Original post by Relaxedexams

There are weak forces of attraction between the layers, hence its slippery property.

[QUOTE=Relaxedexams;37797396. But when you vaguely say that the inter molecular forces of attraction are weak, you can assume that intermolecular forces of attraction between molecules of the same layer are being talked about...

What did you mean when you wrote the earlier post? Your's was the most vaguest , almost confusing me (thats why i am replying)

Reply 608

Relaxedexams

2

Original post by (◕ ‿ ▒r▀▀

No you didnt mean it. Read what you wrote below

But NOW you mean IT

What did you mean when you wrote the earlier post? Your's was the most vaguest , almost confusing me (thats why i am replying)

What I meant when I wrote the earlier post was that graphite has no intermolecular forces of attraction, like in a simple molecular substance like water for example. That is why I stated that graphite is a giant covalent substance and also asked if the forces between layers were being talked about.

Reply 609

NilFBosh

3

can anyone tell me how to find the concentration in g/dm3...there's a question in the last part of hte ;ast question in jan 2012 paper 2...sumone help!

Reply 610

harrietx123x

10

i'm terrible at chemistry! good luck everybody in the last exam tomorrow x

Reply 611

bob12321

Original post by NilFBosh

can anyone tell me how to find the concentration in g/dm3...there's a question in the last part of hte ;ast question in jan 2012 paper 2...sumone help!

Number of mole = mass/RAM

If you know moles and RAM find mass...

Conc = mols/vol

Use that mass value instead of mols

HOWEVER- THEY WILL NEVER ASK I DON'T THINK FOR A RESULT IN G/dm3 - only mols/dm3

Check If you have read the question wrong!

This was posted from The Student Room's iPhone/iPad App

Reply 612

NilFBosh

3

doez anyone know tha answers for that question where a table came and we had to write the precipates.the question came for our paper

Reply 613

sweetzaini16

Original post by harrietx123x

i'm terrible at chemistry! good luck everybody in the last exam tomorrow x

goodluck to u too!! we sail in da same boat!! :frown:

Reply 614

Relaxedexams

2

Original post by NilFBosh

doez anyone know tha answers for that question where a table came and we had to write the precipates.the question came for our paper

It was precipitate, no precipitate and precipitate.

Reply 615

Big-Daddy

13

Original post by Relaxedexams

It was precipitate, no precipitate and precipitate.

I believe calcium and barium made precipitates and potassium no precipitate?

Reply 616

NilFBosh

3

Original post by Relaxedexams

It was precipitate, no precipitate and precipitate.

thats great..thats what i got but what was what? i think i got sumthing like dis

precipate of....

no precipitate

precipitate of...

Reply 617

must try harder.

4

does anyone know what we have to know about rusting for tomorrow's exam? I seem to have no notes whatsoever!! :s-smilie:

Reply 618

Niema20

5

Original post by must try harder.

does anyone know what we have to know about rusting for tomorrow's exam? I seem to have no notes whatsoever!! :s-smilie:

You need to know that it occurs in the presence of oxygen and water, that its chemical formula is Fe2O3.nH20, and what methods of protection from rusting there are: galvanising, coating, alloying ect. I think that's all, sorry if I've missed anything!

Reply 619

must try harder.

4

Original post by Niema20

You need to know that it occurs in the presence of oxygen and water, that its chemical formula is Fe2O3.nH20, and what methods of protection from rusting there are: galvanising, coating, alloying ect. I think that's all, sorry if I've missed anything!

thank you soo much! :smile:

iGCSE 2012 Chemistry Discussion

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you