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# OCR Chemistry: Trends and Patterns module watch

1. Oh, right. I said that lone pairs repel more than bonded pairs.....but it was in the wrong context..i was talking about the chlorine lone pairs.

Would i still get a mark?
2. PCl4+ has 8 electrons (4 bonding pairs) in its outer level, and is tetrahedral in shape. The bond angle is 109.5 degrees.
3. Right...would i get 1/3 or 2/3...

I drew the correct diagram. Then I said in the question that it'd be Square planar, because the lone pairs repel more than bonded pairs. (referring to Chlorine)
4. (Original post by jseldis)
Oh, right. I said that lone pairs repel more than bonded pairs.....but it was in the wrong context..i was talking about the chlorine lone pairs.

Would i still get a mark?
If in different context would have got full marks! But marks were for shape so I imagine that marks are for;
1) Tetrahedral, or 109.5 degrees
2)Saying there are no lone pairs so all electron pair repulsions are equal

And the mark for drawing it right i guess
5. (Original post by Nazmoth)
If in different context would have got full marks! But marks were for shape so I imagine that marks are for;
1) Tetrahedral, or 109.5 degrees
2)Saying there are no lone pairs so all electron pair repulsions are equal

And the mark for drawing it right i guess
I got the second mark then, because i mentioned the lack of lone pairs on the Phosporous too. Thanks for the help mate, it's nice to know i'm not a complete ****!
Might have got more than i thought on this!

Did everyone get something really long for the one with two half equations?
6. BTW way did everyone remember to simplify that ionic equation in Transition Elements. There were waters and H+'s on both sides of equation so had to simplify it. I nearly forgot untill i went back at end and checked!
7. Ah *******s i hope we didn't have to do that on the super-long half equation one...
8. (Original post by jseldis)
I got the second mark then, because i mentioned the lack of lone pairs on the Phosporous too. Thanks for the help mate, it's nice to know i'm not a complete ****!
Might have got more than i thought on this!

Did everyone get something really long for the one with two half equations?
I can't remember what one it was because there was one in transition elements and i got short term memory for equations lol!
9. (Original post by jseldis)
Ah *******s i hope we didn't have to do that on the super-long half equation one...
Can you remember what things were involved to jog my memory!

I was on about one with Cr2O72- in i think when you had to do 8H+-6H+ to simplify it. That's why it was two marks- also had to do it with water!
10. Oh god i had forgotten about that lol! Don't have clue what I put now, that was on T+P the one i was on about was on TE, but i know your already getting annoyed about people using this thread for TE! So i won't talk about it lol.

What did it react with? Was it Al or Fe or something...
If it was then i would have put something like this- also are you sure it wasnt MoO3 not 4?

MoO3 + 2Al -> Al2O3 + Mo

I can even remember to be honest i didn't really think about it!
11. Acidic something.
12. (Original post by jseldis)
Acidic something.
Ah to be honest I can't remember question, but you've made me worried now! I wanna see the paper!
13. Those papers were really easy I thought. The last question about Copper was easy marks.

Transition metals was slightly harder. Dunno if I drew the D orbital shapers the right way around stupidly. But whatever.

The last bit talking about the % purity...80% anyone?

no more exams for me!

14. http://www.chemguide.co.uk/inorganic...thermstab.html
Scroll down to the bottom, there is a table of thermal decomposition enthalpies.

THEY'RE ALL POSITIVE!
15. (Original post by Daxx)
Those papers were really easy I thought. The last question about Copper was easy marks.

Transition metals was slightly harder. Dunno if I drew the D orbital shapers the right way around stupidly. But whatever.

The last bit talking about the % purity...80% anyone?

no more exams for me!

Yep 80.01% the rounded he he! I thought they were easy too- well the bits i can remember- I can always remember the hard bits of exams but seen as i can't remember much of these two at all I must have found it all easy. I also messed up the shapes of d-orbitals- I remember doing that!

I drew dx2-y2 wrong and then crossed it out, as i did it in pen, and then wrote little note to marker telling him/her to mark the scruffy one scrawled beside the box. I checked answer in textbook after and I had changed it to right shape but they might not give mark cus it was out of the box. The other one I just drew completely wrong!
17. (Original post by andiroo)
http://www.chemguide.co.uk/inorganic...thermstab.html
Scroll down to the bottom, there is a table of thermal decomposition enthalpies.

THEY'RE ALL POSITIVE!
Nice one in this case it was Endothermic, but there are examples when thermal decomposition is majorly exothermic, for example Nitroglycerin, or however you spell- you know the stuff that goes
!!!!**BANG**!!!!!

But everyone who put -339 kJ/mol for this is wrong i'm afraid- it's a big fat +!

Anyway people should work out the sign of the enthalpy by drawing correct enthalpy cycle, and then check the sign using reasoning, not just guess that it's positive!
18. The purity one everyone's on about.....Which paper was it on? The 80% one i mean...
19. (Original post by jseldis)
Yeah last question on the Transition Metals paper.

On the Trends Paper, the question just after the enthalpy one:

Was the purity of [some compound with 7H2O] around 75 76 or 77.8%

can't remember what I put.

you had to factor in the mass of the water.

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