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

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Q3:

n=50/2x(23+3x14) [2x because there are 2 moles NaN3.]
n= 5/13

3n=V/24 [3x because there are 3 moles of N2.]
3x5/13 x 24 =V
27.69 = V

The answer is (C) which is 27.7


Q9:

One molecule of HCl dissipates one H+ ion. Now looking at the options:
(A) Ethanoic Acid [It is weak acid and cannot dissipate the H+ ion completely.]
(B) Nitric Acid [The formula is HN)3. Each molecule can dissipate one H+ ion, same as HCl.]
(C) Sodium Hydroxide [It doesn't even dissipate H+ ion!!.]
(D) Sulphuric Acid [H2SO4 dissipates 2 H+ ions per molecule, twice that of HCl.]

So the answer is (B),


Q18: [I couldn't do it. Will try again soon.]

Q37:

1 All bond angles are approximately 120o. [This is true. I hope you know why.]
2 It will undergo electrophilic addition reactions. [Yes they undergo electrophlic addition because of presence of double bonds.]
3 It will undergo nucleophilic addition reactions. [Yes they undergo nucleophlic addition because of presence of lone pairs on Oxygen.]

So answer is (A).

Q39:

First of all, alkanes are not soluble. Arene rings are alkanes which aren't soluble. This gives direct answer of option 1 being correct. Option 1 is a Aldehyde which are oxidized to Carboxylic acids, which are quite soluble! So answer is (D).
Note: Option 2 is also an aldehyde and form a carboxylic acid but with poor solubility due to presence of arene ring. Option 3 is a Ketone and cannot be easily oxidized further.

(If I'm wrong somewhere, please correct me. I got my answers this way which are all correct.)

Can u plz help me with these MCQ's of May/June 2002
2, 4, 5, 6, 7, 8 and 23.
I'll b really greatful.

 

[KWIKIW]

Do you know how to do Qs 17 in 01/O/N/2005?
I don't know what a ligand is and I am confused about how to do this qs.
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w05_qp_1.pdf

 

[1597.2217]

Can u plz help me with these MCQ's of May/June 2002
2, 4, 5, 6, 7, 8 and 23.
I'll b really greatful.

I'm sorry I don't have the question of MJ02. Will you please post the questions here?

 

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I'm sorry I don't have the question of MJ02. Will you please post the questions here?

2. As a simplification, an adult human can be considered to have a daily diet of 1.80 kg carbohydrate (eppirical formula CH2O).
Which mass of CO2 does a person produce each day if all carbohydrate eaten is digested and oxidised?
A. 0.267 kg
B. 0.800 kg
C. 1.32 kg
D. 2.64 kg

4. A slow stream of water from a tap can be deflected by an electrostatically charged plastic rod because water is a polar molecule.
Why is a water molecule polar?
A. Molecules are bonded together by hydrogen bonds.
B. The oxygen and hydrogen atoms ave different electronegativities.
C. The oxygen atoms has two lone pairs of electrons.
D. water is a able to dissociate into ions.

5. Why does copper wire conduct electricity when a potential difference is applied?
A. Bonding electrons in the crystal lattice move.
B. Copper(II) ions move to the cathode.
C. The atoms of copper become ionised.
D. The crystal lattice breaks down.

6. Flask X contains 1dm3 of helium at 2kPa pressure and flask Y contains 2dm3 of neon at 1kPa pressure.
If the flasks are connected at constant temperature , which is the final pressure?
A. 1 1/3 kPa.
B. 1 1/2 kPa.
C. 1 2/3 kPa.
D. 2 kPa.

7. When heated solid iodine readily forms iodine vapour.
What does this information suggest about the nature of the particles in these two physical states of iodine?
Solid Vapour
A. ionic atomic
B. ionic molecular
C. molecular atomic
D. molecular molecular.

8. Which statement about the enthalpy change of formation of carbon dioxide is correct?
A. It is equal to the standard enthalpy change of combustion of carbon.
B. It is equal to twice the bond energy of the C=O bond.
C. It is the energy released when one mole of carbon dioxide is formed from carbon at the temperature of combustion of the carbon.
D. It is the same for carbon dioxide produced from graphite and from diamond.

23. 2-Bromopropane, (CH3)2CHBr, may be used as the starting point for making (CH3)2CHCO2H.
Which of the following sequences would be the most suitable?
A. (CH3)2CHBr -----> (CH3)2CHOH ------> (CH3)2CHCO2H
B. (CH3)2CHBr -----> (CH3)2CHCN ------> (CH3)2CHCO2H
C. (CH3)2CHBr -----> (CH3)2CHOH ------> (CH3)2CHCN -----> (CH3)2CHCO2H
D. (CH3)2CHBr -----> (CH3)2CHCN ------> (CH3)2CHOH -----> (CH3)2CHCO2H

 

[itallion stallion]

Can u plz help me with these MCQ's of May/June 2002
2, 4, 5, 6, 7, 8 and 23.
I'll b really greatful.

In question 2:CH2O+O gives CO2+H2O.so moles of CH2O will be 1800/30=60moles,from equation CH2O:H2O is 1:1 so moles of CO2 will also be 60 then multiply it by its Mr and you will get 2640g, divide it by 1000 and you will get 2.64Kg.
Q4:always remember polarity is due to differance in electronegativity so B.
Q5:as copper is a metal so conduction in it will also be due to electrons so A.
Q7:iodine has a simple molecular structure so it will be molecular in both columns.
Q8: if you write equation for combustion of carbon C+O2 gives CO2+H2O.so it is same for formation of CO2 becaues in combustion we are making one mole of CO2 from its elements which is same in formation also so A
In 23 if u see the product given in question it has one more carbon atom as compapred to its starting reactant, so it means CN has been nucliophiled in placeof Br and then its hydrolysis to make acid.
Hope u got this all.

 

[!>@/^~^\@<!]

In question 2:CH2O+O gives CO2+H2O.so moles of CH2O will be 1800/30=60moles,from equation CH2O:H2O is 1:1 so moles of CO2 will also be 60 then multiply it by its Mr and you will get 2640g, divide it by 1000 and you will get 2.64Kg.
Q4:always remember polarity is due to differance in electronegativity so B.
Q5:as copper is a metal so conduction in it will also be due to electrons so A.
Q7:iodine has a simple molecular structure so it will be molecular in both columns.
Q8: if you write equation for combustion of carbon C+O2 gives CO2+H2O.so it is same for formation of CO2 becaues in combustion we are making one mole of CO2 from its elements which is same in formation also so A
In 23 if u see the product given in question it has one more carbon atom as compapred to its starting reactant, so it means CN has been nucliophiled in placeof Br and then its hydrolysis to make acid.
Hope u got this all.

Thanks a million i really appreciate it . Can you answer all of my questions which i will ask until the exam day coz i have a lot problems. Most of them would be regarding phycial coz i hate physcial chemistry

 

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Thanks a million i really appreciate it . Can you answer all of my questions which i will ask until the exam day coz i have a lot problems. Most of them would be regarding phycial coz i hate physcial chemistry

You forgot question no. 6..

 

[1597.2217]

2. As a simplification, an adult human can be considered to have a daily diet of 1.80 kg carbohydrate (eppirical formula CH2O).
Which mass of CO2 does a person produce each day if all carbohydrate eaten is digested and oxidised?
A. 0.267 kg
B. 0.800 kg
C. 1.32 kg
D. 2.64 kg

4. A slow stream of water from a tap can be deflected by an electrostatically charged plastic rod because water is a polar molecule.
Why is a water molecule polar?
A. Molecules are bonded together by hydrogen bonds.
B. The oxygen and hydrogen atoms ave different electronegativities.
C. The oxygen atoms has two lone pairs of electrons.
D. water is a able to dissociate into ions.

5. Why does copper wire conduct electricity when a potential difference is applied?
A. Bonding electrons in the crystal lattice move.
B. Copper(II) ions move to the cathode.
C. The atoms of copper become ionised.
D. The crystal lattice breaks down.

6. Flask X contains 1dm3 of helium at 2kPa pressure and flask Y contains 2dm3 of neon at 1kPa pressure.
If the flasks are connected at constant temperature , which is the final pressure?
A. 1 1/3 kPa.
B. 1 1/2 kPa.
C. 1 2/3 kPa.
D. 2 kPa.

7. When heated solid iodine readily forms iodine vapour.
What does this information suggest about the nature of the particles in these two physical states of iodine?
Solid Vapour
A. ionic atomic
B. ionic molecular
C. molecular atomic
D. molecular molecular.

8. Which statement about the enthalpy change of formation of carbon dioxide is correct?
A. It is equal to the standard enthalpy change of combustion of carbon.
B. It is equal to twice the bond energy of the C=O bond.
C. It is the energy released when one mole of carbon dioxide is formed from carbon at the temperature of combustion of the carbon.
D. It is the same for carbon dioxide produced from graphite and from diamond.

23. 2-Bromopropane, (CH3)2CHBr, may be used as the starting point for making (CH3)2CHCO2H.
Which of the following sequences would be the most suitable?
A. (CH3)2CHBr -----> (CH3)2CHOH ------> (CH3)2CHCO2H
B. (CH3)2CHBr -----> (CH3)2CHCN ------> (CH3)2CHCO2H
C. (CH3)2CHBr -----> (CH3)2CHOH ------> (CH3)2CHCN -----> (CH3)2CHCO2H
D. (CH3)2CHBr -----> (CH3)2CHCN ------> (CH3)2CHOH -----> (CH3)2CHCO2H

Q2-

First we form a balanced equation of the reaction of oxidation of CH2O.

CH2O + O2 ---> CO2 + H20

Moles of CH20: 1.8/(12+2+16) = 0.06 [You can convert the Kg to g and later convert it back, but this saves time!]
Mass of CO2 produced: n=m/Mr = n x Mr = 0.06 x 12+16+16 = 2.64Kg (D)

We take 0.06 moles here because 1 mole of CH2O gives 1 moles of CO2.

Q4-

Answer is (B) Because of the large difference between electro-negativity of Hydrogen and Oxygen. Oxygen would attract the electrons towards itself hence inducing a partial negative charge. Hence the Hydrogen would have partial positive charge which gives the molecule it's polarity. I hope you're clear with polarity.


Q5-

(A) The bonding in copper is mettalic, which is due to free electrons. These electrons carry the charge hence allow electricity to flow.
(B) The ions cannot move due to very strong mettalic bonding.
(C) This is not true for copper wire, but would be true for electrolysis.
(D) The lattice cannot breakdown otherwise the wire would melt!

So the answer is (A).


Q6 -

Not sure about this one, sorry.


Q7-

Ionic compounds are formed between unlike charged atoms and they have high melting/boiling point. I2 forms covalent/molecular bonds. The answer must be between (C) or (D). I would go with (C) because molecular structure are very large but Iodine isn't.


Q8-
(A) Formation of Co2: C(s) + O2(g) ---> CO2(g). Combustion of C: C(s) + O2(g) ---> CO2(g).
(B) Formation of CO2 means two c=O bonds are formed.
(C) This cannot be the answer because it should be under standard conditions.
(D) This cannot be the answer because the energy required to break the bonds in diamond is very high.

Answer is either (A) or (B). I would go with (B).

Q23-

If you look at the product formed, it has one extra carbon. This mean Cyanide ions are used. You can cut (A) out.
We first need to form a Alcohol which will later be changed to Carboxilic acid. So (B) is out of equation again. It should be (C)!

Please confirm the answers with mark scheme and provide feedback!

 

[!>@/^~^\@<!]

Q2-

First we form a balanced equation of the reaction of oxidation of CH2O.

CH2O + O2 ---> CO2 + H20

Moles of CH20: 1.8/(12+2+16) = 0.06 [You can convert the Kg to g and later convert it back, but this saves time!]
Mass of CO2 produced: n=m/Mr = n x Mr = 0.06 x 12+16+16 = 2.64Kg (D)

We take 0.06 moles here because 1 mole of CH2O gives 1 moles of CO2.

Q4-

Answer is (B) Because of the large difference between electro-negativity of Hydrogen and Oxygen. Oxygen would attract the electrons towards itself hence inducing a partial negative charge. Hence the Hydrogen would have partial positive charge which gives the molecule it's polarity. I hope you're clear with polarity.


Q5-

(A) The bonding in copper is mettalic, which is due to free electrons. These electrons carry the charge hence allow electricity to flow.
(B) The ions cannot move due to very strong mettalic bonding.
(C) This is not true for copper wire, but would be true for electrolysis.
(D) The lattice cannot breakdown otherwise the wire would melt!

So the answer is (A).


Q6 -

Not sure about this one, sorry.


Q7-

Ionic compounds are formed between unlike charged atoms and they have high melting/boiling point. I2 forms covalent/molecular bonds. The answer must be between (C) or (D). I would go with (C) because molecular structure are very large but Iodine isn't.


Q8-
(A) Formation of Co2: C(s) + O2(g) ---> CO2(g). Combustion of C: C(s) + O2(g) ---> CO2(g).
(B) Formation of CO2 means two c=O bonds are formed.
(C) This cannot be the answer because it should be under standard conditions.
(D) This cannot be the answer because the energy required to break the bonds in diamond is very high.

Answer is either (A) or (B). I would go with (B).

Q23-

If you look at the product formed, it has one extra carbon. This mean Cyanide ions are used. You can cut (A) out.
We first need to form a Alcohol which will later be changed to Carboxilic acid. So (B) is out of equation again. It should be (C)!

Please confirm the answers with mark scheme and provide feedback!

Thanks a lot for answering . The answers of MCQ 2, 4 and 5 are correct, the rest aren't. There is somebody else who answered the questions as well, just scroll up the page .

 

[itallion stallion]

Thanks a million i really appreciate it . Can you answer all of my questions which i will ask until the exam day coz i have a lot problems. Most of them would be regarding phycial coz i hate physcial chemistry

i will do so no problem!!

 

[!>@/^~^\@<!]

In question 2:CH2O+O gives CO2+H2O.so moles of CH2O will be 1800/30=60moles,from equation CH2O:H2O is 1:1 so moles of CO2 will also be 60 then multiply it by its Mr and you will get 2640g, divide it by 1000 and you will get 2.64Kg.
Q4:always remember polarity is due to differance in electronegativity so B.
Q5:as copper is a metal so conduction in it will also be due to electrons so A.
Q7:iodine has a simple molecular structure so it will be molecular in both columns.
Q8: if you write equation for combustion of carbon C+O2 gives CO2+H2O.so it is same for formation of CO2 becaues in combustion we are making one mole of CO2 from its elements which is same in formation also so A
In 23 if u see the product given in question it has one more carbon atom as compapred to its starting reactant, so it means CN has been nucliophiled in placeof Br and then its hydrolysis to make acid.
Hope u got this all.

Can you plz ans these MCQ's as well. Nov 2002, mcq 1, 3, 4, 8, 11, 16, 19, 37.
In mcq 29 is option B chiral n obviously how do we solve it.
In mcq 32 why can't it be "ionic bonds" copper does form ionic bonds.
In 33 Na3AlF6 is used for two purposes, lowering the melting point to 970 n improving the electrical conductivity of electrolyte, its not used to purify Al2O3, or is it??

 

[!>@/^~^\@<!]

i will do so no problem!!

I really really REALLY appreciate it, Thanks a bunch!

 

[itallion stallion]

You forgot question no. 6..

Question 6:in the question he has asked for the final pressure which will be (pressure of helium) + (pressure of neon).
so pressure of helium will be volume of (helium/total volume) multiply be helium pressure.u will get this 1/1+2 multiply by 2.now calculate for neon in the same way,2/2+1 multiply by 1.then add them both,2/3+2/3=4/3(answer).hope u got it!!

 

[!>@/^~^\@<!]

Question 6:in the question he has asked for the final pressure which will be (pressure of helium) + (pressure of neon).
so pressure of helium will be volume of (helium/total volume) multiply be helium pressure.u will get this 1/1+2 multiply by 2.now calculate for neon in the same way,2/2+1 multiply by 1.then add them both,2/3+2/3=4/3(answer).hope u got it!!

Got it!!

 

[borabora]

Help!
Q31 of W09/11
A monomer undergoes addition polymerisation. A 1 mol sample of the monomer is completely polymerised.
How many moles of polymer might, theoretically, be formed?
1 1
2 10^(-6)
3 1/(6.02*10^23)

The answer is 2 and 3 only are correct. Why?

 

[itallion stallion]

Can you plz ans these MCQ's as well. Nov 2002, mcq 1, 3, 4, 8, 11, 16, 19, 37.
In mcq 29 is option B chiral n obviously how do we solve it.
In mcq 32 why can't it be "ionic bonds" copper does form ionic bonds.
In 33 Na3AlF6 is used for two purposes, lowering the melting point to 970 n improving the electrical conductivity of electrolyte, its not used to purify Al2O3, or is it??

Question 1:CH4+3O2=CO2+2H2O mole ratio of CH4 to CO2 is 1:1 so CH4 will produce 10 cm3 of CO2.
C2H6+3.5O2=2CO2+2H20 so mole rario of C2H6 to CO2is 1:2 so C2H6 will produce 20cm3 of C02.so total will be 10+20=30.so alkali will absorb 30 cm3 of CO2.
Q3 is asking about second ionisation energy.see from the data booklet,the element which has nearest to Al is the answer.I think its Ni.
Q4:the one that has the lowest mp will be thw answer.i think answer will be alkane cuz alcohol will have hydrogen bond will aldehyde and option c will be polar thus will have higher mp.
Q8:2gram of hydrogen will have 1moles.so it means if there is one mole only then there will be pressure of 'p'(as said in question).so in option c we have 1 gram of hydrogen which will have o.5 mole and we also have 2 gram of D2 which will also have 0.5 moles so combined will be one mole and pressure 'p' so c is answer.in option a there is o.5 moles,option b there are 2 moles and in d there are 0.625 moles so noone will have pressure of 'p'.
question 11:too lenghty and not getting answer, will tell later!
question 16 C guess not sure.
question 19:simply learn this fact that mitrogen is present in large amount,
it has also come in an another paper too.
Q37:but-2-ene has formula CH3CH=CHCH3 so the double bonded carbon have two different things attached to it so it can have.in but-1-ene CH2=CHCH2CH3, the first double bonded carbon has two hydrogen attached which they are same so it wont have cuz when that part rotate there will be no change.
q29:yeah option b is chiral but not acidic,d is both acidic and chiral.in c there is ester group not carboxylic.
q32:there are no ionic bond present in copper itself.question is about its structure not its compounds.
q33.forget the purification we know that it is used as a electrolyte and lowering mp.so stick with that and option 3 states it s uesd as an electrlolyte so it is correct!hope u got all these!

 

[!>@/^~^\@<!]

Question 1:CH4+3O2=CO2+2H2O mole ratio of CH4 to CO2 is 1:1 so CH4 will produce 10 cm3 of CO2.
C2H6+3.5O2=2CO2+2H20 so mole rario of C2H6 to CO2is 1:2 so C2H6 will produce 20cm3 of C02.so total will be 10+20=30.so alkali will absorb 30 cm3 of CO2.
Q3 is asking about second ionisation energy.see from the data booklet,the element which has nearest to Al is the answer.I think its Ni.
Q4:the one that has the lowest mp will be thw answer.i think answer will be alkane cuz alcohol will have hydrogen bond will aldehyde and option c will be polar thus will have higher mp.
Q8:2gram of hydrogen will have 1moles.so it means if there is one mole only then there will be pressure of 'p'(as said in question).so in option c we have 1 gram of hydrogen which will have o.5 mole and we also have 2 gram of D2 which will also have 0.5 moles so combined will be one mole and pressure 'p' so c is answer.in option a there is o.5 moles,option b there are 2 moles and in d there are 0.625 moles so noone will have pressure of 'p'.
question 11:too lenghty and not getting answer, will tell later!
question 16 C guess not sure.
question 19:simply learn this fact that mitrogen is present in large amount,
it has also come in an another paper too.
Q37:but-2-ene has formula CH3CH=CHCH3 so the double bonded carbon have two different things attached to it so it can have.in but-1-ene CH2=CHCH2CH3, the first double bonded carbon has two hydrogen attached which they are same so it wont have cuz when that part rotate there will be no change.
q29:yeah option b is chiral but not acidic,d is both acidic and chiral.in c there is ester group not carboxylic.
q32:there are no ionic bond present in copper itself.question is about its structure not its compounds.
q33.forget the purification we know that it is used as a electrolyte and lowering mp.so stick with that and option 3 states it s uesd as an electrlolyte so it is correct!hope u got all these!

In MCQ 1 it was written mixture of methane and ethane so i was reacting both of them together with oxygen, in a single equation
In mcq 3, you are right, the nearest is Ni but the ans is Co, why??
And how do we have to do mcq 10, same year, i know all the above 3 options r wrong so that leaves D to be the ans but what if they have given us an option which is considerable, so how do we know by looking at the equation that its exothermic and has large negative enthalpy change of formation??

 

[h4rriet]

Help!
Q31 of W09/11
A monomer undergoes addition polymerisation. A 1 mol sample of the monomer is completely polymerised.
How many moles of polymer might, theoretically, be formed?
1 1
2 10^(-6)
3 1/(6.02*10^23)

The answer is 2 and 3 only are correct. Why?

Because a polymer is made of many monomers. So 1 mole of polymer needs more than just 1 mole of monomer; it needs probably hundreds or thousands. So 1 mole of monomer will yield any number of moles LESS THAN 1 of polymer.

 

[h4rriet]

Do you know how to do Qs 17 in 01/O/N/2005?
I don't know what a ligand is and I am confused about how to do this qs.
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w05_qp_1.pdf

You have to know the reaction that takes place when NH3 is added to AgCl.
AgCl + 2NH3 = [Ag(NH3)3]+ + Cl-. It doesn't act as a base because there's no NH4+ formed. It doesn't act as a reducing agent because nothing is reduced. A ligand is just a complex ion. Now all you have to do is decide whether it's formed with Cl- or Ag+.

 

[!>@/^~^\@<!]

Question 1:CH4+3O2=CO2+2H2O mole ratio of CH4 to CO2 is 1:1 so CH4 will produce 10 cm3 of CO2.
C2H6+3.5O2=2CO2+2H20 so mole rario of C2H6 to CO2is 1:2 so C2H6 will produce 20cm3 of C02.so total will be 10+20=30.so alkali will absorb 30 cm3 of CO2.
Q3 is asking about second ionisation energy.see from the data booklet,the element which has nearest to Al is the answer.I think its Ni.
Q4:the one that has the lowest mp will be thw answer.i think answer will be alkane cuz alcohol will have hydrogen bond will aldehyde and option c will be polar thus will have higher mp.
Q8:2gram of hydrogen will have 1moles.so it means if there is one mole only then there will be pressure of 'p'(as said in question).so in option c we have 1 gram of hydrogen which will have o.5 mole and we also have 2 gram of D2 which will also have 0.5 moles so combined will be one mole and pressure 'p' so c is answer.in option a there is o.5 moles,option b there are 2 moles and in d there are 0.625 moles so noone will have pressure of 'p'.
question 11:too lenghty and not getting answer, will tell later!
question 16 C guess not sure.
question 19:simply learn this fact that mitrogen is present in large amount,
it has also come in an another paper too.
Q37:but-2-ene has formula CH3CH=CHCH3 so the double bonded carbon have two different things attached to it so it can have.in but-1-ene CH2=CHCH2CH3, the first double bonded carbon has two hydrogen attached which they are same so it wont have cuz when that part rotate there will be no change.
q29:yeah option b is chiral but not acidic,d is both acidic and chiral.in c there is ester group not carboxylic.
q32:there are no ionic bond present in copper itself.question is about its structure not its compounds.
q33.forget the purification we know that it is used as a electrolyte and lowering mp.so stick with that and option 3 states it s uesd as an electrlolyte so it is correct!hope u got all these!

How to solve these MCQ's, June 2003, MCQ 2, 8, 10, 12, 18, 27, 33, 29.
In mcq 32 options 1 and 3 r correct so obviously the 2nd one is correct as well, but if we r not sure about the 1st and 3rd options so how do we know that the alkyl chain is soluble in oil droplets??