Chemistry: Post your doubts here!

[princess Anu]

The Haber process for the manufacture of ammonia is represented by the following equation.
N2(g) + 3H2(g) 2NH3(g) ∆H = –92kJ mol–1
Which statement is correct about this reaction when the temperature is increased?

A Both forward and backward rates increase.
B The backward rate only increases.
C The forward rate only increases.
D There is no effect on the backward or forward rate.

Why is the correct answer A? The reaction in exothermic so by increasing the temperature, won't the backward reaction increase only?

When temp is increased, rate increases for both forward & backward. When they ask you for yield, then you can say yield of Nh3 will decrease.

 

[asadalam]

Which mixtures, on heating, produce the gas ND3?
[D = H 2
1 , an isotope of hydrogen]
1 CaO(s) and ND4Cl(s)
2 CH3CN and NaOD in D2O
3 NDH3Cl and NaOD in D2O

So D is like H so we can suppose NDH3Cl as NH4Cl so wouldnt reaction 3 also liberate ammonia?The Ms says only 1,2 are correct.

 

[nehaoscar]

I think you have asked similar questions on this? This question is on intermolecular forces of attraction. HCl has the strongest intermolecular attraction (PD-PD) compared to the other options (VDW).




ammonium salt + base --> salt + water + ammonia

It is "bad" because, the nitrogen nutrient which is meant to be taken in by the plants is lost to the surroundings as ammonia gas.

Thankyou! And yes I always keep thinking of the bond energies...

 

[princess Anu]

These too....plllzzz
View attachment 54857 View attachment 54858 View attachment 54860 View attachment 54861 View attachment 54862

last que: n^2= no of cis trans isomers .where n is the no of double bonds.
2nd last Que : if you find the oxidation no of Ag in the ion (on the product side & on reactant side)it will be +1.. which means it stays the same.. so the rest of the options are wrong

 

[awesomaholic101]

Which mixtures, on heating, produce the gas ND3?
[D = H 2
1 , an isotope of hydrogen]
1 CaO(s) and ND4Cl(s)
2 CH3CN and NaOD in D2O
3 NDH3Cl and NaOD in D2O

So D is like H so we can suppose NDH3Cl as NH4Cl so wouldnt reaction 3 also liberate ammonia?The Ms says only 1,2 are correct.

The 3rd reaction doesn't involve D2O ... it is just the reaction between (Ammonium salt) NDH3Cl + (alkali) NaOD ... so we have only 2 D atoms now, but we actually need 3 D atoms to produce ND3 ...
so probably sth like ND2H or sth is produced instead, but that doesn't matter.

 

[muhammadali233]

Good luck everyone!

 

[asadalam]

The 3rd reaction doesn't involve D2O ... it is just the reaction between (Ammonium salt) NDH3Cl + (alkali) NaOD ... so we have only 2 D atoms now, but we actually need 3 D atoms to produce ND3 ...
so probably sth like ND2H or sth is produced instead, but that doesn't matter.

What do you mean?Then how is 2 correct?

 

[muhammadali233]

What do you mean?Then how is 2 correct?

nai aya ga yah ,itni fikar kyn kartay ho? ik din phele pharana tha? soo jao

 

[awesomaholic101]

What do you mean?Then how is 2 correct?

2 is correct coz water (D2O here) is involved in the alkaline hydrolisis of nitrile

 

[asadalam]

2 is correct coz water (D2O here) is involved in the alkaline hydrolisis of nitrile

Theres alkaline Hydrolysis of nitrile too?How many other groups are able to by hydrolysed by water/naoh/hcl

 

[awesomaholic101]

Theres alkaline Hydrolysis of nitrile too?How many other groups are able to by hydrolysed by water/naoh/hcl

Apparently, there is. God knows! urgh paper 1 is annoying ...

 

[asadalam]

Apparently, there is. God knows! urgh paper 1 is annoying ...

Any other thing that might seem more obscure yet can be asked?

 

[princess Anu]

which year is this from?

Which mixtures, on heating, produce the gas ND3?
[D = H 2
1 , an isotope of hydrogen]
1 CaO(s) and ND4Cl(s)
2 CH3CN and NaOD in D2O
3 NDH3Cl and NaOD in D2O

So D is like H so we can suppose NDH3Cl as NH4Cl so wouldnt reaction 3 also liberate ammonia?The Ms says only 1,2 are correct.

 

[awesomaholic101]

Any other thing that might seem more obscure yet can be asked?

I honestly have no idea ... examiners have twisted brains! genius, yes, but twisted.

 

[asadalam]

which year is this from?

W07

I honestly have no idea ... examiners have twisted brains! genius, yes, but twisted.

Amen to that.

 

[asadalam]

I honestly have no idea ... examiners have twisted brains! genius, yes, but twisted.

Can you explain these:
40 Fats and grease that build up on pans used in cooking are esters. Pans which are dirty from fats
or grease may be cleaned by heating them with a reagent that will react with the ester group.
What may be used to clean such pans by this reaction?
1 vinegar - aqueous ethanoic acid, CH3CO2H
2 alcohol - ethanol, C2H5OH
3 baking powder - sodium hydrogencarbonate, NaHCO3

 

[The Sarcastic Retard]

If you can find them,post the links...

You just can do that yourself... go few pages back..

 

[Studydayandnight]

The products obtained by cracking an alkane, X, are methane, ethene and propene. The mole fraction of ethene in the products is 0.5. What is the identity of X?

A C6H14
B C8H18
C C9H20
D C11H24

Correct answer is B.

 

[shazmina]

http://onlineexamhelp.com/wp-content/uploads/2014/08/9701_s14_qp_11.pdf
Question 3.......Help please!!!!!!!! The Ans is D
My doubt is why cant the answer be C????

 

[The Sarcastic Retard]

The products obtained by cracking an alkane, X, are methane, ethene and propene. The mole fraction of ethene in the products is 0.5. What is the identity of X?

A C6H14
B C8H18
C C9H20
D C11H24

Correct answer is B.

http://openstudy.com/updates/528895aee4b0b3376511f73a