Chemistry: Ethanoic Acid

AoifeN

Could anyone tell me, or point me in the direction of, the results for the examining the properties of ethanoic acid thingy? Please?

lovechem

Test with litmus paper. Its an acid so it should turn blue litmus red!

cHaTbOx

AoifeN wrote: »

Could anyone tell me, or point me in the direction of, the results for the examining the properties of ethanoic acid thingy? Please?

Do you have chemistry Live? its on page 376

Turquoise

I was wondering this myself. I think she means the the ones on page 378, and there are no results for them in the book? I'm kinda just praying they won't come up seeing as it was on last year...

AoifeN

Yeh, I've two textbooks and no results Should have gotten them earlier only I well, forgot or couldn't be arsed or something. I have to try and track some people down on Bebo for them

salman85

AoifeN wrote: »

Yeh, I've two textbooks and no results Should have gotten them earlier only I well, forgot or couldn't be arsed or something. I have to try and track some people down on Bebo for them

it came up last year it wont be up again

100%

or i am jumping off a cliff

lovechem

heard a lot of talk about ethanoic acid titration in school today. did one when i got home, its so easy no wayyyyyyyyyyyy could they put it on for HL. Or could they?! :rolleyes:

equilibrium exps?????????

starting to get nervous.

Last night of chemistry EVER!!

pocket aces

lets hope soap doesnt come up :eek:

lovechem

they'd so do that just to be evil like.

Oh industrial or atmospheric? Industrial has only come up twice!!

Turquoise

lovechem wrote: »

they'd so do that just to be evil like.

Oh industrial or atmospheric? Industrial has only come up twice!!

I'm PRAYING that is something to do with options, because I have NO idea what you're talking about?

Soap better not come up!

salman85

lovechem wrote: »

heard a lot of talk about ethanoic acid titration in school today. did one when i got home, its so easy no wayyyyyyyyyyyy could they put it on for HL. Or could they?! :rolleyes:

equilibrium exps?????????

starting to get nervous.

Last night of chemistry EVER!!

hey lovechem i didnt go to my teacher's chem thing so i couldnt tell u his pred as i told u i would but im waiting on a friend to bebo me

also, vinegar titration is very likely to come up, have it prepared (esp the dilution factor where you have to multiply by 4 to get original moles per litre, same with bleach)

Turquoise

Off topic slightly - why is the disodium salt of edta used?!

salman85

Turquoise wrote: »

Off topic slightly - why is the disodium salt of edta used?!

because its a pure stable soild (its a primary standard)

lovechem

eaier to dissolve.

that would be if the dilution factor is 4 tho ya

say the dilution factor is 10 it would be multiply by 10 right???

salman85

yes if you are taking 25cm3 and making it up to 250cm3 it would be 10 :O dont know where i got that 4 from haha

Turquoise

salman85 wrote: »

because its a pure stable soild (its a primary standard)

Thanks for that.
Another question, in the determination of dissolved oxygen, do we need to know all those balanced equations for the various bits? I know its really unlikely to come up, but I'm trying to cover myself here. I could just avoid it I guess...

salman85

Turquoise wrote: »

Thanks for that.
Another question, in the determination of dissolved oxygen, do we need to know all those balanced equations for the various bits? I know its really unlikely to come up, but I'm trying to cover myself here. I could just avoid it I guess...

if ur talking about the wrinkler or w/e method we havent even done that :O we only did the titration

Turquoise

But don't you have to do all that before the titration?
I guess I just won't do it, I'm safe leaving one experiment.

salman85

Turquoise wrote: »

But don't you have to do all that before the titration?
I guess I just won't do it, I'm safe leaving one experiment.

no

what we did was took a tap water sample (dont even need to fill up volumetric) use a pipette 25cm3 goes in conical with the indicator eirchrome black T

edta goes into the burette

you titrate

boom


oh wait my bad ur talking about BOD biological oxygen demand

yes u need to know that inside out mate,

winkler's reagents are KI and NaOH

and add MnSO4 and water

it will form a white precipitate (manganeese hydroxide) which turns brown
add h2so4
it will dissapear and turn red/yellow

100 cm3 of this goes into the conical flask it appears like I2

burette = Na2S2O3 (thiosulfate)

when it turns straw yellow, add starch indicator

titrate until blue black becomes clear

this sort of titration came up last year thats why i didnt learn it but its unlikely to come up

Turquoise

That's to test the hardness of water, not the dissolved oxygen content - they're different.

salman85

read the huge edit before u fail leaving incase its up :O

but here is my prediction

q1 kmno4/bleach/(vinegar)
q2 clove oil/ethyne
q3 temprature vs rate
q4 random stuff
q5 bohr limitations, sigma/pi bonding (benzene) mendeleev vs mosley ionisation energies
q6 fuels, delta H calculation, may be the internal combustion engine
q7 reflux, conversions (aldehydes vs ketones)
q8 water
q9 equilibrium
q10 radio activity, gases, ph
q11 hess's law, o3 mechanism

salman85

Turquoise wrote: »

That's to test the hardness of water, not the dissolved oxygen content - they're different.

no hardness titration is the EDTA one this is "mandatory exp estimation of dissolved oxygen by redox titration"

BOD of diluted waste here is how to calculate
subtract the change in PPM
find the dilution factor
multiply

lovechem

salman85 wrote: »

read the huge edit before u fail leaving incase its up :O

but here is my prediction

q1 kmno4/bleach/(vinegar)
q2 clove oil/ethyne
q3 temprature vs rate
q4 random stuff
q5 bohr limitations, sigma/pi bonding (benzene) mendeleev vs mosley ionisation energies
q6 fuels, delta H calculation, may be the internal combustion engine
q7 reflux, conversions (aldehydes vs ketones)
q8 water
q9 equilibrium
q10 radio activity, gases, ph
q11 hess's law, o3 mechanism

oh its gonna be a long night :(:(

Turquoise

Haha, just read the edit. Yeah...think I'm just gonna leave it out, it's too difficult and if I know all the others I should be ok

Turquoise

Do we need to know what's in Fehling's solution? Might as well I guess....ugh.

salman85

Turquoise wrote: »

Haha, just read the edit. Yeah...think I'm just gonna leave it out, it's too difficult and if I know all the others I should be ok

very unlikely to come up any way thisulphate came up last year unless they have gone mad they wont give it but its easy question to get atleast 35 in even though you know **** all you will still be able to tell about the aparatus and calculate

Turquoise

35 is no good, I've no chance of an A if I lose 15 marks on one question....and I kinda need, and want, an A.

salman85

Turquoise wrote: »

35 is no good, I've no chance of an A if I lose 15 marks on one question....and I kinda need, and want, an A.

easiest way to get an A is

do all 3 experiments
question 4/5/6/7/(and the water one)

8 qustions done

if you dont know the experiments then you have to know eq, ph calculations etc and be flawless at the math behind it

Turquoise

I pretty much know all the experiments bar BOD and I'm planning on doing all 3 exp's. Maths elements of the paper generally aren't a problem (touch wood). I know my organic, water, equilibrium, rates and the first 7 chapters really well. In theory I can do it, in practice - we'll see.

salman85

Turquoise wrote: »

I pretty much know all the experiments bar BOD and I'm planning on doing all 3 exp's. Maths elements of the paper generally aren't a problem (touch wood). I know my organic, water, equilibrium, rates and the first 7 chapters really well. In theory I can do it, in practice - we'll see.

BOD isnt really an experiment but its something which comes up in the long question just know this it would come up in water question if it did come up so just know this definition

BOD is the amount of oxygen used up by micro organisms when a sample of oxygen rich water sample is left in the dark for 5 days at 20 degrees celcius

dark because it prevents photosynthesis
what does a decrease in oxygen suggest (high biological oxygen demand)
bacteria eat up all the oxygen which in turn kills the fish and this water shouldnt be discharged


good luck not hard to learn but it is handy if u want to do the question on water

Turquoise

Oh, don't get me wrong, I know the BOD theory, I just don't know the experiment.