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OCR AS - Chemistry Unit F322 - Chains, energy and resource - REVISION!

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methanol fuel cell

Original post by Nkhan

formation question was -1239

I got -10 something something...

You definitely right?

Reply 682

yesioo

I wrote feedstock for cracking

Better than my answer!...I put anti-freeze :laugh:

Reply 683

Joseppea

Anyone doing OCR physics in a couple of weeks? :biggrin:

Reply 684

RedDevilThing

Original post by timkench

whats better, high percentage yield or atom economy?

I put atom economy.

Original post by Joseppea

.................hydrolysis is nucleophilic substitution right? O_O

Yep.

Reply 685

Nkhan

Original post by Joseppea

.................hydrolysis is nucleophilic substitution right? O_O

yes, and mention heterolytic fission!

Reply 686

bubblebuddy

I just put that methanol was used as starting material to create new chemical substances :/

Reply 687

Yarpie

You could probably state either as long as you explained yourself well. It just said explain your answer so neither is incorrect and the marks would be for explaining your choice.

Reply 688

racheatworld

Original post by timkench

whats better, high percentage yield or atom economy?

I don't think it will matter in terms of marks because it said in your opinion.

I put percentage yield, as this measures the efficiency of converting reactants into products and for ethanol production in industry a high conversion of reactants into products is more important for a good yield. Also, I put with fermentation the reaction will always produce CO2, so the atom economy will never be 100%

Reply 689

ChessMister

I hate these threads :frown:

but I can't keep myself out

What did yall get for the ester?

Reply 690

786girl

for the hess cycle were the arrows pointing DOWN or UP? it said find formation but it has combustion values helpp

Reply 691

Yarpie

Original post by 786girl

methanol fuel cell

thanks for writing in really big letters.

Reply 692

racheatworld

Original post by 786girl

methanol fuel cell

The question said other than a fuel?

Plus that isn't on the spec.
The spec for uses of alcohols is:
Alcohol drinks (usually from fermentation though)
Fuels
Solvents (eg: methylated spirits)
Feedstock for the production of other organic chemicals

So except fuel and solvents I put, feedstock.

Reply 693

racheatworld

Original post by ChessMister

I hate these threads :frown:

but I can't keep myself out

What did yall get for the ester?

Ethyl propanoate is the correct answer.

Reply 694

Joseppea

Original post by 786girl

for the hess cycle were the arrows pointing DOWN or UP? it said find formation but it has combustion values helpp

I put them pointing down as our chemistry teacher always said

"For combustion Hess' Law Triangle the products

BURN IN HELL!" :eek:

That was echoing in my head the whole time :redface:

............so pointing down. xD

Reply 695

shuty

Original post by nereik6794

Wrong

i got -1279

Reply 696

Moody Rabbi

I got positive 1000 something because the arrows had to point down on hess' cycle cause the values given were for enthalpy change of combustion.

Reply 697

KatsG

Original post by 786girl

for the hess cycle were the arrows pointing DOWN or UP? it said find formation but it has combustion values helpp

I don't think you had to draw Hess's cycle just get the enthalpy change right.

Reply 698

anil10100

For other uses of methanol I put as a cleaning agent, LOL.

I put that I think percentage yield is more important, because the if the percentage yield is low, that is matter that is physically lost. If the atom economy is low, then you just have to find a use for the waste products and you can make it 100%, but I dunno, hated that paper, a compilation of my very worst topics.

Reply 699

nereik6794

Original post by racheatworld

You can't use Methanol in alcoholic drinks. Otherwise you would be unable to find your way to the toilet in the morning to 'whitey' due to being blind.