Chemistry Specimen Paper?

[SuperXDE]

Assalamu Alikum~! ( Peace be upon you )

I've been answering the theory questions in my book , but it seems that the book doesn't provide any answers except for numerical questions ( Protons , Neutrons , Electrons ... etc ) , and I have a couple of questions that seem important but unfortunately they are from a Specimen paper ( Ahh...The mystery ) which I can't find anywhere , nor can I find any mark scheme for it , So if anyone knows where I could download it , please tell me..

Here are some of the questions :

Q3) Redox reactions involve the transfer of electrons, Oxidation is the loss of electrons and reduction is the gain.
a) i) Describe the colour change observed when acidifed potassium manganate(IV) is reduced.
ii ) Suggest a suitable reducing agent for this reaction

b) Chromium(III) chloride is changed into potassium chromate(VI). Is this change oxidation , or reduction? Give a reason for your choice

c) A piece of paper is coated with a layer of silver(I) chloride. It is used in this experiment

I don't have the image , but I will try to describe

First Image : A Grey cross on a white paper , the paper is coated with a layer of Silver(I) chloride , and the cross is a thick cardboard cross , arrows on the paper are indicating that paper is exposed to light.

Second Image : A grey paper with a white cross on it. Exposed to light turned grey , cross removed underr cross still white.

i ) Explain why the silver(I) Chloride that was not exposed to the light remained white but that which was exposed turned grey.
ii ) Write an equation for the reduction of the silver(I) ion.
iii) What difference would using a brighter light make?
iv) What is an important application of this reaction?

d) The diagrams show an example of electrolysis and of a cell

The first ( cell ) diagram , Zinc Electrode on the left , lead electrode on the right , bubbles of gas around the lead electrode , dilute sulphuric acid is the electrolyte , and there is a voltmeter in the circuit

The second (electrolysis) diagram , Circuit with power source , carbon electrodes , molten lead bromide is the electrolyte and it is heated.

i ) One of the above reactions is exothermic , State , giving a reason , which one.
ii) How could you tell from the cell experiment which is the more reactive , zinc or lead?
iii) Name the products of the electrolysis of molten lead bromide.
Product at negative electrode : ?
Product at positive electrode : ?

e ) To compare the reactivity of lead , manganese , silver and iron , each metal was added to a solution containing the positive ion of a different metal. The results of this experiment are given in the table below.

Pb : with Mn2+ , No reaction , with Ag+ Reaction , with Fe2+ , No reaction
Mn : With Pb2+ reaction , with Ag+ Reaction , with Fe2+ reaction
Ag : with Pb2+ no reaction , with Mn2+ no reaction , with Fe2+ no reaction.
Fe : with Pb2+ reaction , Mn2+ no reaction , Ag+ reaction.

i) Write the four metals in order of reactivity.
ii) Which metals most readily forms positive ions?
iii) Which ions is the best oxidising agent ?

Specimen Paper Q3

Q4 ) One use of the polymer , polyacrylonitrile , is to make carbon fibres. The monomer, acrylonitrile, is made by the following reaction : 2CH3 - CH = CH2 + 2NH3 + 3O2 -> 2CH2 = CH - CN + 6H2O

a ) Propene is made by the thermal cracking of the naphtha fraction of petroleum. This is a mixture of alkanes, C4 to C10

i ) Name the technique used to obtain naphtha from petroleum.
ii) Predict the formula for the C10 alkane. C10....?
iii) Write a symbol equation for the cracking of hexane (C6H14) to form propene

b) Ammonia is manufactured by the Haber Process
Forward reaction is exothermic
N2(g) + 3H2 (g) <===> 2NH3 (g) , 450C 200 atmospheres pressure.

i) Explain why a high pressure increases the % of ammonia in the equilibrium mixture
ii) At 300 C, The yield of ammonia would be greater. Why is this temperature not used?

c) The repeat unit of the polymer polyacrylonitrile is shown below :

--CH2--CHCN--

This is not the formula , i can't draw it over here .. -_-" unfortunately , but here is a simple explanation , A carbon attached to 2 Hydrogens , on the left , and that carbon is attached to another carbon and both of these carbons have a free bond on their sides , and the second carbon is attached to CN , and Hydrogen.


Try answering these specimen questions , hope they are helpful , I am stuck at A , B of Question 3. -_- they need thinking.

 

[XPFMember]

Waalaikum as salam wa rehmatullah!!

Q3) Redox reactions involve the transfer of electrons, Oxidation is the loss of electrons and reduction is the gain.
a) i) Describe the colour change observed when acidifed potassium manganate(IV) is reduced.
ii ) Suggest a suitable reducing agent for this reaction

i)purple to colourless
ii) u can write ethanol cuz in that reaction too this colour change occurs!

b) Chromium(III) chloride is changed into potassium chromate(VI). Is this change oxidation , or reduction? Give a reason for your choice

it is oxidation cuz there's an increase in the oxidation state!

i ) Explain why the silver(I) Chloride that was not exposed to the light remained white but that which was exposed turned grey.
ii ) Write an equation for the reduction of the silver(I) ion.
iii) What difference would using a brighter light make?
iv) What is an important application of this reaction?

i)refer J_08 ist variant Q6b please,sorry but i dont have time-have to revise!!
ii)Ag+ + e- => Ag
iii) more darker black instead of grey
iv)photography
--------u may find all these (similar) in june 08....--

d) The diagrams show an example of electrolysis and of a cell

The first ( cell ) diagram , Zinc Electrode on the left , lead electrode on the right , bubbles of gas around the lead electrode , dilute sulphuric acid is the electrolyte , and there is a voltmeter in the circuit

The second (electrolysis) diagram , Circuit with power source , carbon electrodes , molten lead bromide is the electrolyte and it is heated.

i ) One of the above reactions is exothermic , State , giving a reason , which one.
ii) How could you tell from the cell experiment which is the more reactive , zinc or lead?
iii) Name the products of the electrolysis of molten lead bromide.
Product at negative electrode : ?
Product at positive electrode : ?

i)cell-produces voltage-energy produced
ii)zinc-bubbles is below less reactive
iii)lead metal
bromine gas
I just saw u needed only a and b !! :x
anyway hope u understood that!!

 

[SuperXDE]

Waalaikum as salam wa rehmatullah!!

Q3) Redox reactions involve the transfer of electrons, Oxidation is the loss of electrons and reduction is the gain.
a) i) Describe the colour change observed when acidifed potassium manganate(IV) is reduced.
ii ) Suggest a suitable reducing agent for this reaction

i)purple to colourless
ii) u can write ethanol cuz in that reaction too this colour change occurs!

b) Chromium(III) chloride is changed into potassium chromate(VI). Is this change oxidation , or reduction? Give a reason for your choice

it is oxidation cuz there's an increase in the oxidation state!

i ) Explain why the silver(I) Chloride that was not exposed to the light remained white but that which was exposed turned grey.
ii ) Write an equation for the reduction of the silver(I) ion.
iii) What difference would using a brighter light make?
iv) What is an important application of this reaction?

i)refer J_08 ist variant Q6b please,sorry but i dont have time-have to revise!!
ii)Ag+ + e- => Ag
iii) more darker black instead of grey
iv)photography
--------u may find all these (similar) in june 08....--

d) The diagrams show an example of electrolysis and of a cell

The first ( cell ) diagram , Zinc Electrode on the left , lead electrode on the right , bubbles of gas around the lead electrode , dilute sulphuric acid is the electrolyte , and there is a voltmeter in the circuit

The second (electrolysis) diagram , Circuit with power source , carbon electrodes , molten lead bromide is the electrolyte and it is heated.

i ) One of the above reactions is exothermic , State , giving a reason , which one.
ii) How could you tell from the cell experiment which is the more reactive , zinc or lead?
iii) Name the products of the electrolysis of molten lead bromide.
Product at negative electrode : ?
Product at positive electrode : ?

i)cell-produces voltage-energy produced
ii)zinc-bubbles is below less reactive
iii)lead metal
bromine gas
I just saw u needed only a and b !! :x
anyway hope u understood that!!

Thanks Jazaak(i) Allahu Khairan , really helped

 

[XPFMember]

wa eyakum

 

[XPFMember]

btw , now i get what was the real case of that matter recently that There's smthng wrong wid the N_03 papers,so thats the specimen paper we have! so one of the 2 papers is specimen & the other is the exam paper!

 

[SuperXDE]

btw , now i get what was the real case of that matter recently that There's smthng wrong wid the N_03 papers,so thats the specimen paper we have! so one of the 2 papers is specimen & the other is the exam paper!

Where to download it xD?!

 

[XPFMember]

the exam paper is there on freeexampapers but that too doesnt say its specimen paper!!though mark scheme isnt. there!!

 

[SuperXDE]

the exam paper is there on freeexampapers but that too doesnt say its specimen paper!!though mark scheme isnt. there!!

=_=" okay....guess I will have to fetch for it somewhere..

 

[iluvchem]

salam elikom

c) A piece of paper is coated with a layer of silver(I) chloride. It is used in this experiment

I don't have the image , but I will try to describe

First Image : A Grey cross on a white paper , the paper is coated with a layer of Silver(I) chloride , and the cross is a thick cardboard cross , arrows on the paper are indicating that paper is exposed to light.

Second Image : A grey paper with a white cross on it. Exposed to light turned grey , cross removed underr cross still white.

i ) Explain why the silver(I) Chloride that was not exposed to the light remained white but that which was exposed turned grey.
ii ) Write an equation for the reduction of the silver(I) ion.
iii) What difference would using a brighter light make?
iv) What is an important application of this reaction?


thease are my answers.
i)its a photochemical reaction of silver(I) Halide, when exposed to light silver its reduced and silver chloride is decomposed {don't know how many marks the question is}
ii)Ag+ - e---->Ag
iii)brighter light would decompose silver chloride faster
iv)photography