P1 MCQ's preparation thread for chemistry ONLY!!!!

[h4rriet]

v 1 year 2009

Okay... May/June or October/November?!

 

[h4rriet]

can someone plz help me with this papers(http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w09_qp_11.pdf) question no 14,21,31.

14. Phosphorous chloride and oxide are both acidic.
21.
31.

 

[A n g e l a ♥]

Okay... May/June or October/November?!

May june =P


hmm can u please help me out with may\june 2010 v1 Q5&29 =D ?

 

[itallion stallion]

14. Phosphorous chloride and oxide are both acidic.
21.
31.

thanks for q14, plz can u also tell the other two.

 

[itallion stallion]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_11.pdf can someone plz help me with q35.plz explain why in q39 option 3 is wrong, cant the compound have both a double bond and primary alcohol group and react with br2 and Na.thanks

 

[h4rriet]

May june =P


hmm can u please help me out with may\june 2010 v1 Q5&29 =D ?

5. -214 divided by 2 because 2 moles of ICl3 are made. Add that to +38.
29. You have to draw all the alkenes and check for cis-trans isomers.

 

[h4rriet]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_qp_11.pdf can someone plz help me with q35.plz explain why in q39 option 3 is wrong, cant the compound have both a double bond and primary alcohol group and react with br2 and Na.thanks

39. Decolourising aqueous bromine will require a C=C double bond. There isn't any for the compound in 3.

 

[h4rriet]

thanks for q14, plz can u also tell the other two.

Not sure about 21 but 31: a polymer is many monomers, so you'll need much more than one mole of a monomer to get 1 polymer. With 1 mole of monomer, you'll get any number of polymers less than 1, e.g. 0.00001 moles.

 

[abruzzi]

Could anyone please help me with some questions from May/June 2011? I'm uploading the question paper since the link is broken on the site..
Question no. 6
Question no. 25 - Why can't the answer be C?

Thanks

 

[itallion stallion]

39. Decolourising aqueous bromine will require a C=C double bond. There isn't any for the compound in 3.

cant the compound be like this CH3CH=CHOH.thanks alot for the rest.

 

[h4rriet]

Could anyone please help me with some questions from May/June 2011? I'm uploading the question paper since the link is broken on the site..
Question no. 6
Question no. 25 - Why can't the answer be C?

Thanks

6. The answer is A because you see from the a/t graph that acceleration becomes constant at 1/2T. In B the acceleration becomes 0 at 1/2 T, in C the velocity is zero & in D there's increasing acceleration throughout.
25. The fundamental frequency is when lambda is 1/4. The first overtone will be when lambda is 3/4, and the second overtone when lambda is 5/4.

 

[h4rriet]

cant the compound be like this CH3CH=CHOH.thanks alot for the rest.

Two H atoms are missing in your compound.

 

[h4rriet]

May june =P


hmm can u please help me out with may\june 2010 v1 Q5&29 =D ?

11. Barium nitrate decomposes to BaO and the unreactive gas is N2.
24. Attacking group is OH- and leaving group is Br-.
28. When heated with hot, conc., acidified KMnO4, the C=C bonds will break and turn into C=O bonds.
31. Radius is the same always because number of outer electrons is the same always.

 

[abruzzi]

Could anyone please help me with some questions from May/June 2011? I'm uploading the question paper since the link is broken on the site..
Question no. 6
Question no. 25 - Why can't the answer be C?

Thanks

Thanks a lot for the reply.. but the paper I uploaded was of chemistry.
Please help me solve those questions in the chemistry paper..

 

[h4rriet]

Thanks a lot for the reply.. but the paper I uploaded was of chemistry.
Please help me solve those questions in the chemistry paper..

Argh, I apologise. This isn't the first time this has happened! Anyway:
6. The volume of O2 is more, so there must have been more moles of H2O2. More moles -> higher concentration.
25. If an alcohol is to be dehydrated, the C of the C-OH must be attached to a C attached to an H atom.

 

[abruzzi]

Argh, I apologise. This isn't the first time this has happened! Anyway:
6. The volume of O2 is more, so there must have been more moles of H2O2. More moles -> higher concentration.
25. If an alcohol is to be dehydrated, the C of the C-OH must be attached to a C attached to an H atom.

No worries..

For question 25, you mean the Carbon atom attached to the -OH group must be attached to a hydrogen atom?

 

[h4rriet]

No worries..

For question 25, you mean the Carbon atom attached to the -OH group must be attached to a hydrogen atom?

No, the Carbon attached to -OH group must be attached to a Carbon which is attached to a Hydrogen.

 

[abruzzi]

No, the Carbon attached to -OH group must be attached to a Carbon which is attached to a Hydrogen.

So why can't C be the answer? All the carbon atoms attached to the carbon holding the -OH group have a hydrogen

 

[h4rriet]

So why can't C be the answer? All the carbon atoms attached to the carbon holding the -OH group have a hydrogen

I didn't read the question properly. The question asks which alcohol will give the largest number of alkenes when dehydrated. A, B, C & D can all be dehydrated, but some will give more alkenes than others. For example, A & D can give only one alkene, because the C of the COH is attached to only one other C. B can give two structurally different alkenes, because the C of the COH is attached to 2 other Carbon atoms, and both have a Hydrogen atom attached to them. C will give 3 structurally different alkenes, because the C of the COH is attached to 3 Carbons, and all these are attached to Hydrogen atoms. BUT both of the alkenes produced by B will have cis-trans isomers. That'll make the alkenes produced by B 4. It'll give the most number of alkenes upon dehydration.
Tell me if you need more explanation. I'll draw a diagram.

 

[abruzzi]

I didn't read the question properly. The question asks which alcohol will give the largest number of alkenes when dehydrated. A, B, C & D can all be dehydrated, but some will give more alkenes than others. For example, A & D can give only one alkene, because the C of the COH is attached to only one other C. B can give two structurally different alkenes, because the C of the COH is attached to 2 other Carbon atoms, and both have a Hydrogen atom attached to them. C will give 3 structurally different alkenes, because the C of the COH is attached to 3 Carbons, and all these are attached to Hydrogen atoms. BUT both of the alkenes produced by B will have cis-trans isomers. That'll make the alkenes produced by B 4. It'll give the most number of alkenes upon dehydration.
Tell me if you need more explanation. I'll draw a diagram.

Oh yeah.. that was so tricky.

Thanks a lot man.. really appreciate it!