Biology; Chemistry; Physics: Post your doubts here!

[Alpha Destro]

Catalytic Converter converts harmfull gases (NO,CO,HC) into harmless gases
2NO + 2CO ----> 2CO2 +N2
2CO + O2 -----> 2CO2
HC + O2 ------>3CO2 +H2O

Reaction takes place at 500-800c.Steel helps to maintain this temp.
They are lined with Pd,Rh (Catayst)

A catalytic converter turns harmful gases into harmless gases. For example, Catalytic converters are used in Cars. Cars throw out Carbon Monoxide and Nitrogen Dioxide. Both of these gases are harmful.

Catalytic converter oxidises Carbon Monoxide to Carbon Dioxide
And
Reduces Nitrogen Dioxide to Nitrogen thus making these both gases harmless.

Yes yes i know all this , i just wanted to see how many knew that a catalytic conveter also converts unburnt hydro carbons into carbon dioxide and water
i did not know this until i came across a past paper which mentioned this , Hassan1233 is right he mentioned "HC + O2 ------>3CO2 +H2O" a medal to you man
I hope that anyone who did not know this now knows it HA!

 

[Rizwan Javed]

Can someone check out Chemistry D05/P2/Q.9
It is really difficult :O

A more reactive halogen would displace the less reactive one. Displacement reactions are carried out to investigate the trend of reactivity in halogens. Three test tubes are set up containing aq. KCl, KBr, and KI. To these test tubes 2 cm3 of aqueous chlorine is added alternately and colour change noted. The experiment is repeated with aqueous bromine and aqueous iodine, using another set of 3 testubes. The results are tabulated as shown:

the equations for these reactions are:
Cl2 + 2KBr ---> 2KCl +Br2
Cl2 + 2KI ---> 2KCl + I2
Br2 + 2KI ---> 2KBr + I2

 

[Anonymous-BLEH!]

well, distillation means to evaporate and then condense the liquid.........just for example u place pebbles(insoluble impurities) in water and then carry out distillation......ULL GET THE WATER BACK.......3 is also correct, but to some extent.

isnt desalination possible too thn?? we get water afterall

 

[abbas haider]

isnt desalination possible too thn?? we get water afterall

nop... salt i ssoluble in water and so desalination is used to remove souluble solid (salt)....

 

[Anonymous-BLEH!]

nop... salt i ssoluble in water and so desalination is used to remove souluble solid (salt)....

okay...

 

[Netherdrake]

How to make Ethyl Propanoate? Please someone help
In it
Ethanol will be alcohol?
Propanoic will be Carboxylic acid?

Will it be like this?
C2H5OH+C3H5OOH ---> C5H10O2?

 

[Netherdrake]

Can someone solve this question?
5070/22/O/N/13
A5(b)(i)

I don't know how to draw that graph line.

 

[Netherdrake]

Why Aluminium doesnot react with Aqueous Copper(II) sulfate?
Ans. Oxide layer of Aluminium or Copper?

Confused

 

[Rizwan Javed]

How to make Ethyl Propanoate? Please someone help
In it
Ethanol will be alcohol?
Propanoic will be Carboxylic acid?

Will it be like this?
C2H5OH+C3H5OOH ---> C5H10O2?

C2H5OH + C2H5COOH ---> C2H5COOC2H5 (Yes, You're correct! )

 

[Rizwan Javed]

Why Aluminium doesnot react with Aqueous Copper(II) sulfate?
Ans. Oxide layer of Aluminium or Copper?

Confused

Aluminium has an unreactive oxide layer on its surface.

 

[Haris Zulfiqar]

Can someone solve this question?
5070/22/O/N/13
A5(b)(i)

I don't know how to draw that graph line.

draw the graph of vol against time, do not write any reading

Why Aluminium doesnot react with Aqueous Copper(II) sulfate?
Ans. Oxide layer of Aluminium or Copper?

Confused

Al has a protective coating of Al2O3 on it because of its reaction with oxygrn in air, this layer protects Al from reacting

 

[Netherdrake]

 

[Netherdrake]

5070/22/O/N/13
B8 (c)

 

[Rizwan Javed]

moles of ethene in 0.4 tonnes= 0.4/28 = 0.014 mol
since only 5% is used, so moles of ethene used= 5/100 *0.014 = 0.0007143 moles

from equ. C2H4: C2H5OH = 1:1
So, moles of ethanol formed = 0.0007143 moles
Therefore,
Mass of ethanol formed = 0.0007143 * (Mr of ethanol) = 0.0007143 * 46 = 0.033 tonnes

(SORRY I DIDN'T CONVERT TONNES INTO GRAMS, BUT IN PAPER YOU ARE BOUND TO CONVERT THEM OTHERWISE YOUR WHOLE CALCULATION WILL BE WRONG! I DID THIS TO AVOID TOO MUCH BIG ANSWERS )

 

[Netherdrake]

 

[Rizwan Javed]

It's C. sulfer dioxide dissolves in water to form H2SO3 (which is a weak acid). So when Na2CO3 is added then CO2 is given off (acid reaction with carbonates)

 

[Haris Zulfiqar]

Plz urgent help needed can anyone tell me plz that the conditions of which reactions should i learn
tomorrow is exams urgent help
thx in advance

 

[Alpha Destro]

Plz urgent help needed can anyone tell me plz that the conditions of which reactions should i learn
tomorrow is exams urgent help
thx in advance

hyrogenation,hydration,fermentation,contact process,haber process,manufacture of esters, thats abt it.

 

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