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View attachment 59025
View attachment 59026
Why can't it be HZ + OH- ==> H2O + Z-
And pls explain the second part of the ms ... addition of base
Adding OH- ... where did the H+ come from ... there's no H+ in the equation :/
What you must understand is that there is actually no such thing as H+ existing by itself. H+ is a proton, and it would be too unstable to stay like that. As soon as it finds an H2O molecule, it binds to it to form the H3O+ ion. So really, whenever we talk about H+ in a solution in chemistry, we mean the H3O+. I suggest you think of H+ and H3O+ as interchangeable terms for the same thing.View attachment 59025
View attachment 59026
Why can't it be HZ + OH- ==> H2O + Z-
And pls explain the second part of the ms ... addition of base
Adding OH- ... where did the H+ come from ... there's no H+ in the equation :/
What you must understand is that there is actually no such thing as H+ existing by itself. H+ is a proton, and it would be too unstable to stay like that. As soon as it finds an H2O molecule, it binds to it to form the H3O+ ion. So really, whenever we talk about H+ in a solution in chemistry, we mean the H3O+. I suggest you think of H+ and H3O+ as interchangeable terms for the same thing.
A weak acid dissociates in a solution by reacting with water. This is what actually happens:
HZ + H2O <-> Z- + H3O+
But sometimes we just ignore the H2O and just say:
HZ <-> H+ + Z-
You can think of it as subtracting H2O from both sides of the equation, but it isn't what happens really.
The weak acid being in a reversible reaction above when placed in water is very useful for us. It can act as a BUFFER.
When acid is added (we say H+ is added), equilibrium shifts to left side based on Le Chatelier's Principle, so change in pH is resisted.
When alkali is added, OH- reacts with "H+" to make H2O molecules; H+ ion concentration is reduced when base is added to buffer.
Le Chatelier Principle means that equilibrium will shift to right to restore this "H+" and so change in pH is resisted again.
Hope that's clear.
Yes thankyou soooo much!What you must understand is that there is actually no such thing as H+ existing by itself. H+ is a proton, and it would be too unstable to stay like that. As soon as it finds an H2O molecule, it binds to it to form the H3O+ ion. So really, whenever we talk about H+ in a solution in chemistry, we mean the H3O+. I suggest you think of H+ and H3O+ as interchangeable terms for the same thing.
A weak acid dissociates in a solution by reacting with water. This is what actually happens:
HZ + H2O <-> Z- + H3O+
But sometimes we just ignore the H2O and just say:
HZ <-> H+ + Z-
You can think of it as subtracting H2O from both sides of the equation, but it isn't what happens really.
The weak acid being in a reversible reaction above when placed in water is very useful for us. It can act as a BUFFER.
When acid is added (we say H+ is added), equilibrium shifts to left side based on Le Chatelier's Principle, so change in pH is resisted.
When alkali is added, OH- reacts with "H+" to make H2O molecules; H+ ion concentration is reduced when base is added to buffer.
Le Chatelier Principle means that equilibrium will shift to right to restore this "H+" and so change in pH is resisted again.
Hope that's clear.
Do you mean instead of H+? Yes!Thanks for the detailed explanation.
So when base is added, the OH- ions, in reality, react with the H3O+ ions?
Rotating the left side of G by 180° actually will not give you F. For this you must try to imagine this compound in 3D.View attachment 59070
So the answer is J
But why not G?? Rotating the left side of G by 180 degrees will give F right?? :/
Ohh! I see ... but so when you rotate it 180 degrees wouldn't it beRotating the left side of G by 180° actually will not give you F. For this you must try to imagine this compound in 3D.
For G we have:
Now, if you were to rotate this 180°, you'd have a CO2H group that GOES INTO the page, and NH2 that COMES OUT of page. Try think about it. You'll see.
- CO2H that COMES OUT of page
- NH2 that GOES INTO the page.
- H that is along same plane as page
Is this what F is? No. F has CO2H that still comes out of page, so it is not identical to G
I have tried thinking about it, but I still think the CO2H group would go into page after 180 rotation.Ohh! I see ... but so when you rotate it 180 degrees wouldn't it be
1. COOH is along the same plane as page
2. NH2 goes into page
3. H comes out of page
like so:
View attachment 59077
Instead of "Now, if you were to rotate this 180°, you'd have a CO2H group that GOES INTO the page, and NH2 that COMES OUT of page."
Haha alrightI have tried thinking about it, but I still think the CO2H group would go into page after 180 rotation.
I don't see how it could be out of page initially, and then become same plane as paper. That would require non-180° rotation.
I may be misunderstanding something though. Let's see what others have to say.
Yep!Haha alright
Just to confirm ... the stick means same plane as paper, the dotted line means into the page and the bold line means out of the page right?
Oh oh ok ... That was news to me. ThanksDo you mean instead of H+? Yes!
What actually happens:
H3O+ + OH- <-> 2H2O
So you see H3O+ donates the proton to OH-, so that TWO water molecules are formed.
We normally simplify this by "subtracting" H2O from both sides:
H+ + OH- <-> H2O
See since this is in three dimensions and not two when you rotate G the COOH which is coming out of the plane of paper would now go into the plane of paper and NH2 would come out,however rotating J from the right side the OH bond will go in and H will come out which is what we want.View attachment 59070
So the answer is J
But why not G?? Rotating the left side of G by 180 degrees will give F right?? :/
Thanks! Okay so I get why it's J but then this small doubtSee since this is in three dimensions and not two when you rotate G the COOH which is coming out of the plane of paper would now go into the plane of paper and NH2 would come out,however rotating J from the right side the OH bond will go in and H will come out which is what we want.
If the temperature of the solution which you're experimenting with rises, then the experiment is exomethermic otherwise if it drops then it'll be endothermic.and can someone please tell me how do we know if an experiment done in Paper 3 exothermic or endothermic?
thank you so muchIf the temperature of the solution which you're experimenting with rises, then the experiment is exomethermic otherwise if it drops then it'll be endothermic.
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