GCSE Edexcel Triple Science (B3, C3, P3)

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Reply 40

Angelo12231

Original post by LeEastafrican

0.072g = 66cm3
1g= 66/0.072
1g= 916.7 1 mol = 916.7
916.7 x 24 =22000 cm3 volume= mole x 24

idk something like that

lol for a 2 mark question? its correct however.

Reply 41

LeEastafrican

Original post by Angelo12231

lol for a 2 mark question? its correct however.

i guess so!

Reply 42

LeEastafrican

Original post by LeEastafrican

i guess so!

or you could find one mole
0.072/24= 0.003
66/0.003= 22000

Reply 43

Angelo12231

Original post by LeEastafrican

i guess so!

yup

(edited 9 years ago)

Reply 44

Marcusroye98

Original post by LeEastafrican

or you could find one mole
0.072/24= 0.003
66/0.003= 22000

I understand now :-D! just wondering what formulas you used?:-)

Reply 45

LeEastafrican

Original post by Angelo12231

btw, 1 gram? can it be one mole? i thought the mole is equal to the mass in grams of Ar or Mr of element/compound?

oh yh, ignore my method and stick to the formula
volume = mole x 24
i think that is the formula,
66/0.003 = 22000 or something not sure.

Reply 46

katinthehat

Hi all,

Don't suppose anyone knows how to memorize all of C3 in a day? Managed to do B3 but C3 is much more difficult to cram!

Reply 47

Angelo12231

Original post by katinthehat

Hi all,

Don't suppose anyone knows how to memorize all of C3 in a day? Managed to do B3 but C3 is much more difficult to cram!

lol im cramming now... basically cram now and unpick the understanding in the exam from what you have crammed before hand XD

Reply 48

Marcusroye98

Original post by Angelo12231

lol im cramming now... basically cram now and unpick the understanding in the exam from what you have crammed before hand XD

During the electrolysis of copper, why is copper sulfate solution used as an electrolyte?? :L

Reply 49

username1118458

Original post by katinthehat

Hi all,

Don't suppose anyone knows how to memorize all of C3 in a day? Managed to do B3 but C3 is much more difficult to cram!

I crammed for every single Science :redface:

In my opinion it actually works better than revising spread out - you remember more.

I crammed for C3 last year and thought it went pretty well.

Reply 50

Angelo12231

Original post by Marcusroye98

During the electrolysis of copper, why is copper sulfate solution used as an electrolyte?? :L

LOL its because you only want copper to go to the cathode... if you use, i dont know, sodium sulfate then you might get some sodium in the anode and you don't want that... you only want copper. If we were trying to obtain sodium, we would use sodium sulfate electrolyte because we are trying to be as pure as we can. There is no point in purifying when you don't use the type of metal you want to purify as part of an electrolyte...

Sorry, i only just scrapped an A in english language so i cant speak english properly :biggrin:

Reply 51

Marcusroye98

Original post by Angelo12231

Thanks!!!

I am worse hahaha!!

I hope they ask us to draw some esters xD

Reply 52

Angelo12231

Original post by Marcusroye98

Thanks!!!

I am worse hahaha!!

I hope they ask us to draw some esters xD

NOOO :'( i only know the formulas

Reply 53

Marcusroye98

Original post by Angelo12231

NOOO :'( i only know the formulas

I can only work out the formulas by drawing them in the first place xD

Reply 54

Angelo12231

Original post by Marcusroye98

I can only work out the formulas by drawing them in the first place xD

loool oh yeah
i use to do that XD

But general formulas are really simple to learn

Alcohol= Cn H2n+1 OH
Carboxylic = Cn H2n+1 COOH (same as alcohol except 'COOH' instead of 'OH'
ester= alcohol + carboxylic acid

Reply 55

Marcusroye98

Original post by Angelo12231

My chem teacher just walks round the room shouting COOOOOOOOOOOOH at us all the time -____-

Reply 56

Angelo12231

Original post by Marcusroye98

My chem teacher just walks round the room shouting COOOOOOOOOOOOH at us all the time -____-

pahaha she must have drove her car into a chemis-tree

Hey you know how ethanol can be written as C2H5OH... it can also be written as CH3CH20H... how does that show a clearer structure :s-smilie:

and when ethanol + oxygen react its like this:

CH3CH2OH+02=CH3C00H+H20 ... how did they know how many CH or O's in the product -_- how do you know what to write as they react to form product

Reply 57

Marcusroye98

Original post by Angelo12231

pahaha she must have drove her car into a chemis-tree

Hey you know how ethanol can be written as C2H5OH... it can also be written as CH3CH20H... how does that show a clearer structure :s-smilie:

and when ethanol + oxygen react its like this:

CH3CH2OH+02=CH3C00H+H20 ... how did they know how many CH or O's in the product -_- how do you know what to write as they react to form product

YEYE!
You can write it in any order! as long as it makes sense and there is a correct number of elements :smile:

Reply 58

katinthehat

Original post by yellowcopter

I crammed for every single Science :redface:

In my opinion it actually works better than revising spread out - you remember more.

I crammed for C3 last year and thought it went pretty well.

That's very reassuring :cool:

I just get pissed off about science because there's literally no skill application, like in English, it's basically just a memory test. My memory is v. bad = I'm not too good at science exams. Don't get me wrong, I LOVE science, I just don't like the way they test you on it :angry: