**Chemistry...Before/After

Hermione Granger

Hayezer wrote: »

Why are alkenes more reactive than alkanes?
And what was that weird indicator acid colour change thing in the pH question?

I said lower relative molecular mass and unsaturated

Hayezer

Hermione Granger wrote: »

I said lower relative molecular mass and unsaturated

Think I just said very negative double bond, or something :L couldnt think of anything.

Hermione Granger

What did people get for the calculation for 3

sdiff

Lovely paper, though just realised on the last bit of question 2 I forgot to multiply by 60%. How much marks will I lose for that?

leaveiton

Aaaargh keep realising stupid mistakes I made, for the short q about sublevels and orbitals I mixed up orbitals with shells

xGraceTx

Dicksboro_man wrote: »

TMCGY wrote: »

I said homogenous :? And propan-2-ol... uho...

same, homogenous all the way and i also threw in "which demonstrates intermediate compound theory" in case they were looking for it

But the cobalt is in crystallised form usually, and that makes it a solid catalyst against a liquid..? Doesnt it?

finality

Hayezer wrote: »

Why are alkenes more reactive than alkanes?
And what was that weird indicator acid colour change thing in the pH question?

I said the OH- ions in the base remove the H+ ions which creates a strain and so the system is pushed towards the side with the H+ ions to make more of them, so the colour of that side (purple?) predominates.

sdiff

Saracarroll wrote: »

This doesn't matter as it is only the conc that was changed

It does matter - it means that the new yield is half the old one.

sdiff

finality wrote: »

I said the OH- ions in the base remove the H+ ions which creates a strain and so the system is pushed towards the side with the H+ ions to make more of them, so the colour of that side (purple?) predominates.

Same.

Hermione Granger

finality wrote: »

I said the OH- ions in the base remove the H+ ions which creates a strain and so the system is pushed towards the side with the H+ ions to make more of them, so the colour of that side (purple?) predominates.

It definnitely purple. I did a similar question this morning

Sunny!!

for that Q4 levels question

was it

5 and 5

Hermione Granger

think i got 9 and 5

mikechris1919

Sunny!! wrote: »

for that Q4 levels question

was it

5 and 5

I said 3 nd 5 but most likely wron as usual!

ivanh

xGraceTx wrote: »

I said benzene for 6 c, the one about mtbe and what used to be added to fuel. And I said it was stopped cos it was carcinogenic... Any hope for me?

That's what I said too, hopefully they'll accept it

Mista

Hayezer wrote: »

Think I just said very negative double bond, or something :L couldnt think of anything.

I said that other atoms bond easily with it.. like with the Br mechanism :P

ei.sderob

5 sublevels and 9 orbitals.

Helloxoxo

Does anyone know for definite the answers for 3 (c) and (e) ? Hope they're marked easily

Sunny!!

do people think methanal would be accepted as a volatile liquid?

Mista

Sunny!! wrote: »

do people think methanal would be accepted as a volatile liquid?

No, its boiling point is -22C.. you have to get the vapour back into a liquid to measure its mass.

Sunny!!

Mista wrote: »

No, its boiling point is -22C.. you have to get the vapour back into a liquid to measure its mass.

ah ok thanks anyway!

RedTexan

Do you reckon I'll lose many marks for doing the heat of formation backwards and coming out with 224 KJmol-1

ChemHickey

RedTexan wrote: »

Do you reckon I'll lose many marks for doing the heat of formation backwards and coming out with 224 KJmol-1

Probably -3 at most. They might see it as just forgetting to throw in the minus sign so you should be grand really. Won't (hopefully not) change your grade.

RedTexan

ChemHickey wrote: »

Probably -3 at most. They might see it as just forgetting to throw in the minus sign so you should be grand really. Won't (hopefully not) change your grade.

Yera I don't think so, I got 10 questions done and was fairly confident with the most of it! I'd say it shouldn't be too much!

Sunny!!

you know in question 1 when they ask a primary standard reagent? will it be enough saying its a solution of known concentration


and i just took guesses and this is probarly rubbish

the liquid adjusted to the 0 mark? i said at eye level to bottom of meniscus


and the pipette for acuracy?

probarly aload of rubbish:(

Mista

Sunny!! wrote: »

you know in question 1 when they ask a primary standard reagent? will it be enough saying its a solution of known concentration


and i just took guesses and this is probarly rubbish

the liquid adjusted to the 0 mark? i said at eye level to bottom of meniscus


and the pipette for acuracy?

probarly aload of rubbish:(

Cheer up, they look right! For burette I just said open tap until what you said :pac:

Sunny!!

Mista wrote: »

Cheer up, they look right! For burette I just said open tap until what you said :pac:

gutted with the paper! the paper its self was fine! should have done more work on my part:(

RedTexan

ChemHickey wrote: »

Probably -3 at most. They might see it as just forgetting to throw in the minus sign so you should be grand really. Won't (hopefully not) change your grade.

Yeah I had the equation written out next to it, as well backwards! Yera, happens.

mrboswell

Rossie17 wrote: »

Yeah me too please? That would be great!!

It's on line here

Yellowstars

what did ye say for Q7 problems arising after adding too much of fluorin or chlorine(there the ones i chose). oh and q8 9(e) the reagent and catalyst to bring about conversion R. and the instantaneous rate at 60 seconds? aaaand 4e.the oxidation/reduction balance?

RedTexan

Yellowstars wrote: »

what did ye say for Q7 problems arising after adding too much of fluorin or chlorine(there the ones i chose). oh and q8 9(e) the reagent and catalyst to bring about conversion R. and the instantaneous rate at 60 seconds? aaaand 4e.the oxidation/reduction balance?

It was the calcium hydroxide and sulphuric acid, I think, making the water either too basic or too acidic. Hydrogen and a nickle catalyst

Hayezer

I said adding too much of the acid would make water acidic, corroding water pipes. I said too much chlorine would make water undrinkable? Bit of a guess.

ChemHickey

Yellowstars wrote: »

what did ye say for Q7 problems arising after adding too much of fluorin or chlorine(there the ones i chose). oh and q8 9(e) the reagent and catalyst to bring about conversion R. and the instantaneous rate at 60 seconds? aaaand 4e.the oxidation/reduction balance?

I didn't do q7 but too much chlorine would be untasteful. I would have picked the acid/base saying too much acid and it would damage teeth, too much base would damage piping.

hydrogen with nickel catalyst

I got like 27? I think I'm wrong!

I can't remember the ox,red question.

BL1993

Hayezer wrote: »

I said adding too much of the acid would make water acidic, corroding water pipes. I said too much chlorine would make water undrinkable? Bit of a guess.

Same. I also mentioned that too much chlorine irritates eyes if you wash your face with the water. :P

Yellowstars

thanks! wb 4b. balanced nuclear reaction? ..also for 7c..would u get away with saying heavy metals kill fish?

ShaunaMoll

Yellowstars wrote: »

what did ye say for Q7 problems arising after adding too much of fluorin or chlorine(there the ones i chose). oh and q8 9(e) the reagent and catalyst to bring about conversion R. and the instantaneous rate at 60 seconds? aaaand 4e.the oxidation/reduction balance?

For the problems arising after adding too much fluorine, you could say that it gives the water a bad taste, and too much chlorine irritates skin membrane.

I'm guessing you meant Q8 (d) - reagent was h2 and catalyst was Ni?

Didn't do the rate of reaction question!

ChemHickey

Btw, it's too much FLUORIDE not fluorine... lets hope you didn't say fluorine.

ei.sderob

I got a pretty small answer for the instantaneous rate as I put time on the x axis. Think it's right though, I mean I can't think of anything I did wrong for it...:/

Hayezer

ei.sderob wrote: »

I got a pretty small answer for the instantaneous rate as I put time on the x axis. Think it's right though, I mean I can't think of anything I did wrong for it...:/

I got 0.00 something i think :pac:

ChemHickey

Time was supposed to go on the y axis wasn't it?

ei.sderob

Hayezer wrote: »

I got 0.00 something i think :pac:

I think that's right like. I mean it can't be too large a number as it's grams per second like! Pretty hopeful for the A1. What did ye say for the pipette filler? That was odd.

ShaunaMoll

ChemHickey wrote: »

Btw, it's too much FLUORIDE not fluorine... lets hope you didn't say fluorine.

Hahaha, yeah I said NaF - my brain is pretty much fried right now, typing skills aren't the best!

ei.sderob

ChemHickey wrote: »

Time was supposed to go on the y axis wasn't it?

Really? I mean if you're in control of time then shouldn't it be on the x? I'm probably wrong though!

abbeymate

Well everyone, I got the 8 test tubes the for ethene experiment but feel terrible after remembering that I didnt multiply by two for the titration calculations :-S Such a stupid mistake! :-/ Anyway, before I take a few heavy swigs of concentrated alcohol from my conical flask in depression, how much marks will I lose? As in in my answer for grams per litre completely wrong seeing as I got the first part wrong?

FaoiSin

ei.sderob wrote: »

Really? I mean if you're in control of time then shouldn't it be on the x? I'm probably wrong though!

Nah you're right as far as I know. I didn't like that question that much as I wasn't sure if my calculations were accurate so I did organic.

Did anyone else find the organic really nice?

finality

ChemHickey wrote: »

Time was supposed to go on the y axis wasn't it?

I think time was the x axis. Because the rate is loss of grams/time

and if time is on the x axis then that equals the slope of the graph. If time's on the y axis you'd have to invert the slope to get the instantaneous rate.

ChemHickey

finality wrote: »

I think time was the x axis. Because the rate is loss of grams/time

and if time is on the x axis then that equals the slope of the graph. If time's on the y axis you'd have to invert the slope to get the instantaneous rate.

Ah sure, I won't be counting that question anyway! :L I made stupid mistakes in all of that question!

I did 10questions and all three parts in 10 and 11 so I should be covered for the A1... touch-wood.

And I was only going by the way the graph I thought would look.. and I hate rates anyway! :L

ei.sderob

abbeymate wrote: »

Well everyone, I got the 8 test tubes the for ethene experiment but feel terrible after remembering that I didnt multiply by two for the titration calculations :-S Such a stupid mistake! :-/ Anyway, before I take a few heavy swigs of concentrated alcohol from my conical flask in depression, how much marks will I lose? As in in my answer for grams per litre completely wrong seeing as I got the first part wrong?

What part are you talking about multiplying by two for? You had to divide by two for the finding the mass of Na2Co3 and then the HCL titration was as normal. I could be completely misinterpreting your question though!

ChemHickey

ei.sderob wrote: »

What part are you talking about multiplying by two for? You had to divide by two for the finding the mass of Na2Co3 and then the HCL titration was as normal. I could be completely misinterpreting your question though!

I think he/she means that they didn't put HCL over two, then multiplying across by two then when you need to get the M on it's own. I think

finality

abbeymate wrote: »

Well everyone, I got the 8 test tubes the for ethene experiment but feel terrible after remembering that I didnt multiply by two for the titration calculations :-S Such a stupid mistake! :-/ Anyway, before I take a few heavy swigs of concentrated alcohol from my conical flask in depression, how much marks will I lose? As in in my answer for grams per litre completely wrong seeing as I got the first part wrong?

I don't think you're supposed to multiply by 2. Is this question 1? You're told it's a 0.05 molar solution - that's 0.05 moles per litre. It doesn't matter that you've only made 500cm^3 of it as it's still a 0.05 molar solution.

Even if you got the moles per litre wrong, you'd still get the marks for the grams per litre provided your work for that part of the question was correct.

ei.sderob

ChemHickey wrote: »

Ah sure, I won't be counting that question anyway! :L I made stupid mistakes in all of that question!

I did 10questions and all three parts in 10 and 11 so I should be covered for the A1... touch-wood.

And I was only going by the way the graph I thought would look.. and I hate rates anyway! :L

I can NEVER find the time to do extra questions in Chem exams! Are you doing something with Chemistry in college? Just going by your name like...