Edexcel CHEMISTRY DOUBTS!!!!

[Meticulous]

10b)

I know what is your mistake. You counted the number of moles of ALL the reactants. Wrong!

Pressure ONLY affects GASEOUS molecules. It has NO effect on solids.

LHS: 3 moles   RHS: 2 moles

Therefore, decreasing pressure will shift equilibrium to left, decreasing the product yield.

Clear?

[Saladin]

10b)

I know what is your mistake. You counted the number of moles of ALL the reactants. Wrong!

Pressure ONLY affects GASEOUS molecules. It has NO effect on solids.

LHS: 3 moles   RHS: 2 moles

Therefore, decreasing pressure will shift equilibrium to left, decreasing the product yield.

Clear?

Correction, sulphur is a solid. You do not count that.

[Meticulous]

Correction, sulphur is a solid. You do not count that.

Exactly, thats what I just said. On the right, there are only 2 moles. You don't count the sulpher.

[Saladin]

Exactly, thats what I just said. On the right, there are only 2 moles. You don't count the sulpher.

oopsies, my bad, i was thinking it was more pressure!

Silly me.

but wat abt a?

[Meticulous]

LOL..its alright.

For a, check the previous page.

[Saladin]

LOL..its alright.

For a, check the previous page.

Now I just feel like smacking my head now. Whenever I see negative, I think of endothermic! LOL

Sorry for the inconvenience.

[Meticulous]

It's alright. It happens..lol

Just as soon as you see delta h is negative, put the word exo on the forward, and endo on the backward reaction.

That way you wont get confused.

[Summer :]]

There is a considerable concern about the depletion of the 'ozone layer'. Ozone, 03, is constantly being formed in the upper atmosphere by oxygen molecules reacting with oxygen atoms. These atoms are formed when other oxygen molecules absorb high energy Ultraviolet radiation and undergo homolytic bond fission

O2 --> O. + O. (Reaction 1)
O. + O2 --> O3 (Reaction 2)
The ozone absorbs ultraviolet radiation and breaks down to oxygen molecules and atoms.
O3 --> O2 + O. (Reaction 3)
Another reaction, which is not light dependent, also removes ozone:
O3 + O. --> 2O2 (Reaction 4)
Over time ozone and oxygen concentrations reach a steady state.

Question is: Reaction 2 has an enthalpy change of -100 kj mol-1 and Reaction 4 an enthalpy change of -390 kg mol-1. Assuming that Reactions 1 and 2 are followed by Reaction 4, show how this results in the upper atmosphere warming up by effectively converting light energy into heat energy.
Calculate the amount of heat produced per mole of oxygen molecules


 

[Saladin]

There is a considerable concern about the depletion of the 'ozone layer'. Ozone, 03, is constantly being formed in the upper atmosphere by oxygen molecules reacting with oxygen atoms. These atoms are formed when other oxygen molecules absorb high energy Ultraviolet radiation and undergo homolytic bond fission

O2 --> O. + O. (Reaction 1)
O. + O2 --> O3 (Reaction 2)
The ozone absorbs ultraviolet radiation and breaks down to oxygen molecules and atoms.
O3 --> O2 + O. (Reaction 3)
Another reaction, which is not light dependent, also removes ozone:
O3 + O. --> 2O2 (Reaction 4)
Over time ozone and oxygen concentrations reach a steady state.

Question is: Reaction 2 has an enthalpy change of -100 kj mol-1 and Reaction 4 an enthalpy change of -390 kg mol-1. Assuming that Reactions 1 and 2 are followed by Reaction 4, show how this results in the upper atmosphere warming up by effectively converting light energy into heat energy.
Calculate the amount of heat produced per mole of oxygen molecules


 

Where did u get this from?

[GodOfWar]

There is a considerable concern about the depletion of the 'ozone layer'. Ozone, 03, is constantly being formed in the upper atmosphere by oxygen molecules reacting with oxygen atoms. These atoms are formed when other oxygen molecules absorb high energy Ultraviolet radiation and undergo homolytic bond fission

O2 --> O. + O. (Reaction 1)
O. + O2 --> O3 (Reaction 2)
The ozone absorbs ultraviolet radiation and breaks down to oxygen molecules and atoms.
O3 --> O2 + O. (Reaction 3)
Another reaction, which is not light dependent, also removes ozone:
O3 + O. --> 2O2 (Reaction 4)
Over time ozone and oxygen concentrations reach a steady state.

Question is: Reaction 2 has an enthalpy change of -100 kj mol-1 and Reaction 4 an enthalpy change of -390 kg mol-1. Assuming that Reactions 1 and 2 are followed by Reaction 4, show how this results in the upper atmosphere warming up by effectively converting light energy into heat energy.
Calculate the amount of heat produced per mole of oxygen molecules


 

Hmmm... i don't get it 

[Kim]

where did that question come from?

[studz]

guyz could anyone of u be kind enough to explain me about the thermal stability of group 1&2 NITRATES CARBONATES & HYDROXIDES..
i know about it to some extent..but its not that clear to me..!

[leebux101]

oh yes please!!!

[wakemeup]

This might be a little difficult to explain but I'll try. Here's the thing, as you go down the group, the polarisation power decreases. Now, you're probably thinking 'That should make the bond weaker'. But the deal is that carbonates and nitrates are not single atoms. The more polarised they are, the more uneven charge density they have because the cation is mainly pulling just one oxygen atom towards itself. This makes the other part of the carbonate or nitrate ion unwilling to stay with the cation. The more you go down group 2, the more the charge density becomes even around the carbonate or nitrate ion as it is less polarised and the ion is more willing to stay with the cation. So as you go down the group metal carbonates and nitrates become more stable. Hope my explanation didn't confuse you too much.                                                                                       

[leebux101]

so basically...polarising power decreases down the group, attracting ability of the cation decreases cuz charge density decreases (cuz radius increases) so they carb and nit become more stable...down the group, that is.