OCR A 2016 Chemistry A* A-Level Resources

rob_1999

Hi there, I'm new to this, I'm currently in year 12 going to sit my AS Level in Chemistry in May and I'm really struggling with the maths parts of my revision and was hoping someone could help me?Question I have is:-"The student adds a lump of limestone with mass 0.13 g to 25.00 cm3 of 0.1 mol dm -3 hydrochloric acid and stirs until the reaction is finished, the solution is then filtered. The excess acid in the filtered solution reacts with 7cm3 of 0.1 mol dm -3 sodium hydroxide. The equations for the reactions are CaCO3 + 2HCl --> Ca Cl2 + CO2 + H2OHCl + NaOH -->NaCl + H2OCalculate the percentage of calcium carbonate in the limestone."

Any help would be much appreciated.

thanks
Rob

Reply 181

Yesitisi

7

Original post by ForgottenApple

x

I saw you put memrise in your original post and I've just downloaded it, but does it actually work? I went through a couple of questions and I'm not so sure if it tests recognition or recall. Have you personally used it? And what is the best way to use it?

Reply 182

LThomas694

2

That's awful I would be so pissed off! So glad they're changing it after this year

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Reply 183

ForgottenApple

OP

14

Original post by Yesitisi

I saw you put memrise in your original post and I've just downloaded it, but does it actually work? I went through a couple of questions and I'm not so sure if it tests recognition or recall. Have you personally used it? And what is the best way to use it?

I found it helped me. Repetition is key and you'll recall it. Simple as.

Reply 184

CSLady

11

Which legacy papers link to which current specification (before 2015) there seem to be loads with different names. So for example the how far, how fast is the legacy version of ...
Help would be greatly appreciated !

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Reply 185

UnknownAnon

9

Original post by CSLady

Which legacy papers link to which current specification (before 2015) there seem to be loads with different names. So for example the how far, how fast is the legacy version of ...
Help would be greatly appreciated !

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How far and how fast seems to link to rates.

Reply 186

CSLady

11

Original post by UnknownAnon

How far and how fast seems to link to rates.

So is that equilibrium energeticas and elements or is that just part of that A2 module ?

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Reply 187

thad33

12

Original post by CSLady

So is that equilibrium energeticas and elements or is that just part of that A2 module ?

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How far and how fast is the first chapter of F325

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Reply 188

CSLady

11

Original post by thad33

How far and how fast is the first chapter of F325

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Ok thank you so i am guessing the other papers are the rest of the modules/ chapters

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Reply 189

thad33

12

Original post by CSLady

Ok thank you so i am guessing the other papers are the rest of the modules/ chapters

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I know there's a transition elements one. I can't remember what the energy one is though. I think it's a case of doing the first year of legacy, figuring out which is useful and then just do the same for the following years

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Reply 190

Exotic-L

10

can anyone give me a link to instrumental analysis past papers pls. i do WJEC and they have a new spec so they don't have many questions on this topic i dont know how to find other past paper questions from other boards. i looked at many revision websites nd ive had no luck.

thanks

Reply 191

UnknownAnon

9

Original post by Exotic-L

can anyone give me a link to instrumental analysis past papers pls. i do WJEC and they have a new spec so they don't have many questions on this topic i dont know how to find other past paper questions from other boards. i looked at many revision websites nd ive had no luck.

thanks

Do you mean like mass spectroscopy questions? proton NMR? Carbon nmr? If so, then there are some questions in F324 and F322 for OCR.

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Reply 192

Exotic-L

10

Original post by UnknownAnon

Do you mean like mass spectroscopy questions? proton NMR? Carbon nmr? If so, then there are some questions in F324 and F322 for OCR.

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yes and IR spectrometry.
thank you!!

Reply 193

Exotic-L

10

Can someone tell me where the 5 proton environments are pls

(edited 8 years ago)

Original post by chanda01

Each of the 3H (alcohol, ester and aldehyde) are equal to 3, then the 2 H on the phenol ring on the carbons on each side of the aldehyde are equal to one.. then the last C on the phenol (opposite the ester.. that carbon)

Thank you!
Can u explain how u grouped the 3 protons on the ring into environments pls

Reply 195

tvdfan

11

Hi everyone... I don't know which exam this thread is targeted for exactly but I have a question I'd be grateful if anyone could help with. It's one of the examination questions for module 1 in the Heinemann textbook for F322, it asks:

explain why both cis and trans hex-3-ene react with Br2 to produce the same structural formula?

I've looked at the MS answer but dont understand it... thank you

Reply 196

tvdfan

11

Also for question 2(d) on page 144 of the ocr textbook, the second skeletal formula 2,3-diethylpentane doesn't look right to me! it looks more like 2,3-dimethylpentane! i'm so confused can someone help?

Reply 197

ForgottenApple

OP

14

Original post by Exotic-L

yes and IR spectrometry.
thank you!!

Hey bud use physics and maths tutor to target problem areas with by topic questions :smile:

Reply 198

UnknownAnon

9

Original post by tvdfan

Hi everyone... I don't know which exam this thread is targeted for exactly but I have a question I'd be grateful if anyone could help with. It's one of the examination questions for module 1 in the Heinemann textbook for F322, it asks:

explain why both cis and trans hex-3-ene react with Br2 to produce the same structural formula?

I've looked at the MS answer but dont understand it... thank you

Isn't it because a cis-trans sterioisomer has the same structural formula but different arrangements of atom in space. So they produce the same product (the only difference being the arrangement of Br in space to form cis and trans)

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Reply 199

dpoojaraa

3

Original post by chanda01

Each of the 3H (alcohol, ester and aldehyde) are equal to 3, then the 2 H on the phenol ring on the carbons on each side of the aldehyde are equal to one.. then the last C on the phenol (opposite the ester.. that carbon)

I don't understand how the 2H on the phenol ring, each side of the aldehyde are equal to 1? Surely that's 2 environments? Please can you elaborate how it's 1?

OCR A 2016 Chemistry A* A-Level Resources

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