Cambridge Chemistry Challenge

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Reply 640

dragonkeeper999

Original post by Theafricanlegend

I putting 0.1 but its not accepting it :frown:

Are you sure you looked that up right?

Reply 641

dragonkeeper999

Does anyone have any past papers for the L6 paper other than the 2011 one? If so, could you please post a link? Thanks.

Reply 642

Oromis263

Original post by dragonkeeper999

Does anyone have any past papers for the L6 paper other than the 2011 one? If so, could you please post a link? Thanks.

Pretty sure it only started last year, sorry! :smile:

Original post by Theafricanlegend

ugh silver is fudging annyoning, probably tried all combos

Have you got the list of the dates? I tried a couple of guesses at first, but when you look at the dates, you should notice that there are certain elements which HAVE to go in certain places, and from there you can slot in the others by inspection. :smile:

Reply 643

Oromis263

Original post by Theafricanlegend

can anyone tellme if the area density of graphene is 0.77 mg/msquared is right?

That is correct. :smile:

Reply 644

Oromis263

Original post by Theafricanlegend

uh oh roentgenium looks very hard!

I'll post some useful pointers, but only look at them if you get ultra stuck. :smile:

Molecule 1

Molecule 2

Molecule 3

Reply 645

dragonkeeper999

Original post by Theafricanlegend

yes? what is it? i cant find anything on methane in jupiter :frown:

I searched for the 'keywords' ie the element then the number into google, and a table comparing all the values including the required one popped up...
HINT/ complete giveaway: If you're still stuck... try tripling your original value...
edit: just read the other posts - thought you said 0.1... yh, no percent sign! :smile:

(edited 11 years ago)

Reply 646

dragonkeeper999

Original post by Oromis263

Pretty sure it only started last year, sorry! :smile:

Aha. that explains why my 2 hours of searching found nothing! oh well... thanks for preventing me wasting more of my time!

Reply 647

Oromis263

Original post by Theafricanlegend

yeah haha after another hour or so i found the right percentage :biggrin:

D , done silver and gold now on to the last bit! any help will be muchly appreciated, i thought the first molecule has 2 isomers the second has 15 and the third has 30 but its giving me the wrong answer any pointers??? id llove to finish this puzzle before school :biggrin:

Well, what I noticed was:

Small Clue

(edited 11 years ago)

Reply 648

Oromis263

Original post by Theafricanlegend

qaww thats so good! what year are you? how are you so good? what did u use? thaanks!!

I'm year 13, and I just like puzzles. :smile:

I used my brain and some Google really. Placed top 10 for UK, but I took part every month since it started this year. :smile:

Reply 649

SnakehipsTTC

Original post by Oromis263

I'm year 13, and I just like puzzles. :smile:

I used my brain and some Google really. Placed top 10 for UK, but I took part every month since it started this year. :smile:

Could you post the area density for graphene please? Can't find a correct value anywhere! :smile:

Reply 650

Oromis263

Original post by dmccririck

Could you post the area density for graphene please? Can't find a correct value anywhere! :smile:

It was a tricky one to find actually, had a wee bit of help myself. :smile:

I'll put it in expand as other people might not want to see it.

Graphene

(edited 11 years ago)

Reply 651

Oromis263

Original post by Theafricanlegend

milligrams you mean?

Ah yes, my bad :smile:

Cheers

Reply 652

dragonkeeper999

Original post by Theafricanlegend

yeah haha after another hour or so i found the right percentage :biggrin:

first molecule - 2 isomers (optical), third molecule - 30 isomers. correct.
Second molecule:There is one central atom and five other atoms (from group 7) bonded to it. This makes a trigonal bi-pyramidal structure. There are two atoms vertically bonded and three atoms horizontally bonded. Therefore, you could have, for example, F and Br vertically, and Cl, I and At horizontally. There are therefore 10 combinations in which the atoms can be bonded either vertically or horizontally (5C2). Look back at the first molecule, which had two optical isomers (reflections). Each combination of the second molecule would also have two isomers. Therefore the total number of isomers is...

(edited 11 years ago)

Reply 653

D4rth

Did anyone do the Lower Sixth Exam today?

Reply 654

gingerbreadman85

Myr 12s did it today, looked tough. Nice range of questions..... Please remember the usual rules on exam papers though (the paper is live till the 22nd).