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Chemistry and Physics AS paper 12 MCQS

syed1995

syed1995

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bogus said:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_11.pdf
q27 ...i dont get it syed1995
Click to expand...

Which electromagnetic wave would cause the most significant diffraction effect for an atomic
lattice of spacing around 10^–10 m?

Only those would cause a diffraction whose Wavelength is close to 10^-10 m .. cuz those which have a greater wavelength won't be able to pass .. and those smaller will pass without any deflection.

Answer should be D.

Radio = 10^5 til 10^-1
Micro = 10^-1 to 10^-3
Infa-red = 10^-3 to 4x10^-7
Visible light = 4x10^-7 to 7x10^-7
Ultra violet light = 7x10^-7 to 10^-8
X-Rays = 10^-8 to 10^-12
Gamma Rays = 10^-10 to 10^-14


PLEASE Check the values for the wavelength of these.. I just told them off the top of my head.. I think they may be wrong.. Please let me know If they are correct :)
 
syed1995

syed1995

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salvatore said:
Please help me with the questions below..
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_11.pdf
Question no. 16, 21, 28

I'll appreciate an explanation.. thanks!
Click to expand...

Hey salvatore! How are your papers going mate? :) I hope you are doing well!

No. 16 C .. in Cl2 it's 0.. then in ClO^- it will be Cl+(-2)=-1 Oxidation no of Cl=+1

so the change is from 0 to 1 .. +1 change.

No 21 C

An organic compound J reacts with sodium to produce an organic ion with a charge of –3... Means it has 3 -OH groups.

J reacts with NaOH(aq) to produce an organic ion with a charge of –1... meaning it has 1 -COOH group which reacts with NaOH.

So 2 OH groups and 1 COOH group. which is only available in C.

No. 28 No Clue! I thought the answer was C but that's wrong :( I need help in this one!
 
salvatore

salvatore

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syed1995 said:
Hey salvatore! How are your papers going mate? :) I hope you are doing well!

No. 16 C .. in Cl2 it's 0.. then in ClO^- it will be Cl+(-2)=-1 Oxidation no of Cl=+1

so the change is from 0 to 1 .. +1 change.

No 21 C

An organic compound J reacts with sodium to produce an organic ion with a charge of –3... Means it has 3 -OH groups.

J reacts with NaOH(aq) to produce an organic ion with a charge of –1... meaning it has 1 -COOH group which reacts with NaOH.

So 2 OH groups and 1 COOH group. which is only available in C.

No. 28 No Clue! I thought the answer was C but that's wrong :( I need help in this one!
Click to expand...
Helloo!
My papers are going on well bruv.. just left with two multiple choice papers.. then party time!! :)
Hope yours are going on well too..

No. 16.. *punch me in the face* I was thinking of something else.. it was so simple.
No. 21.. perfectly understood.. thanks!
No. 28.. I'll let you know if I find any solution for that, please do the same if you get the answer.

Thanks a lot :)
 
syed1995

syed1995

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hope4thebest said:
please explain this anyone View attachment 28077
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1 And 2 only.. so B?

Since with 1 .. Ammonia plus alkali gives.. Ammonium salt.. (2 NH3 + 3 CaO = Ca3N2 + 3 H2O .. the equation isn't in course) YOU JUST NEED TO KNOW THAT CaO is a base.
With 2.. P4O10 is not acidic without water... and undergoes the reaction.. P4O10 + 4 NH3 + 3 O2 = 4 NH3PO4

With 3 however.. H2SO4 and NH3 being acid and base will undergo nuetralization reaction instead getting dried.. So 3 Is incorrect. And answer is B.
 
syed1995

syed1995

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salvatore said:
Helloo!
My papers are going on well bruv.. just left with two multiple choice papers.. then party time!! :)
Hope yours are going on well too..

No. 16.. *punch me in the face* I was thinking of something else.. it was so simple.
No. 21.. perfectly understood.. thanks!
No. 28.. I'll let you know if I find any solution for that, please do the same if you get the answer.

Thanks a lot :)
Click to expand...

Haha Alhamdullilah My papers are going fine as well :) Now just need to score 32+ in both Chem and Phy MCQs (INSHALLAH) and be done with AS!

No worries mate.. that happens sometimes.. yea I will let you know if I find answer for 28.
 
H

hope4thebest

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syed1995 said:
1 And 2 only.. so B?

Since with 1 .. Ammonia plus alkali gives.. Ammonium salt.. (2 NH3 + 3 CaO = Ca3N2 + 3 H2O .. the equation isn't in course) YOU JUST NEED TO KNOW THAT CaO is a base.
With 2.. P4O10 is not acidic without water... and undergoes the reaction.. P4O10 + 4 NH3 + 3 O2 = 4 NH3PO4

With 3 however.. H2SO4 and NH3 being acid and base will undergo nuetralization reaction instead getting dried.. So 3 Is incorrect. And answer is B.
Click to expand...

I also thought the same but MS says its D
 
syed1995

syed1995

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hope4thebest said:
I also thought the same but MS says its D
Click to expand...

Ah We are stupid mate! There is already water present in Aqueous NH3 or else it won't need to be dried! I didn't knew this.. but further research gave me this reaction ..

The reaction goes as follows ! --> P4O10 + H2O --> H3PO4

then H3PO4 + NH3 --> (NH4)3PO4 !

so as H3PO4 is acidic this reaction is also acid-base reaction..!

Thanks man.. Because of you.. A really huge concept of mine has gotten clear :)
 
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can somebody please help me out with these
1.Lead(IV) chloride will oxidise bromide ions to bromine. The Pb4+ ions are reduced to Pb2+ ions in
this reaction.
If 6.980 g of lead(IV) chloride is added to an excess of sodium bromide solution, what mass of bromine would be produced?
A 0.799g B 1.598g C 3.196g D 6.392g

5
10 Sulfur dioxide is used as a preservative in wine making.
The following equations describe how sulfur dioxide dissolves. H O + SO HSO – + H+
223
HSO – + H+ SO 2– + 2H+ 33
Which statement about these two reactions is correct? A HSO – acts as a base.
3
B SO2 acts as an oxidising agent.
C SO 2– acts as an acid.
D SO 2– acts as a reducing agent.

6. An aqueous solution was prepared containing 1.0 mol of AgNO3 and 1.0 mol of FeSO4 in 1.00 dm3 of water. When equilibrium was established, there was 0.44 mol of Ag+(aq) in the mixture.
Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq) What is the numerical value of Kc?
A 0.35 B 0.62 C 1.62 D 2.89


25 Use of the Data Booklet is relevant to this question.
2.76 g of ethanol were mixed with an excess of aqueous acidified potassium dichromate(VI). The reaction mixture was then boiled under reflux for one hour. The organic product was then collected by distillation.
The yield of product was 75.0 %.
What mass of product was collected?
A 1.98g B 2.07g C 2.70g D 4.80g

10
28 A reaction between chlorine and propane in ultraviolet light produces two isomeric
monochloropropanes, C3H7Cl, as products. Which information about this reaction is correct?
type of bond fission in initiation step
expected ratio of 1-chloropropane to 2-chloropropane produced

expected ratio of 1-chloropropane to 2-chloropropane produced
type of bond fission in initiation step
heterolytic 1:1
heterolytic 3:1
Homolytic. 1:1
homolytic. 3:1
 
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