Edexcel CHEMISTRY DOUBTS!!!!

[Deadly_king]

It can be because it not instantaneous-induced diploe, its induced-induced dipole which is more stronger because it stays for a longer time at a particular energy without breaking.

I don't think so.

Permanent dipole is always present in polar molecules whereas induced dipole occurs only when there is a disturbance in the distribution of charges within a molecule.

[Master_Key]

Take an example of water, it is a polar molecule. The degree of polarisation varies, it is not the same always so it seems that these dipole forces must be breaking and forming all the time.

[mdwael]

HCl is indeed a polar molecule within which there exist permanent dipole-permanent dipole forces of attraction. These forces occurs between the partially negatively charged chlorine and the partially positively charged hydrogen from another molecule. This is because chlorine is electronegative, hence it attracts the shared pair of electrons towards itself.

Now let's get back to your question :
Q : Name the strongest intermolecular force present in liquid HCl
I would have said permanent dipole - permanent dipole forces of attraction.

I can't explain the reasoning of the marking scheme. I guess there might be a mistake or something like that. I'll advise you to consult a tutor.

I totally agree with every word you said, thats what my textbook said and thats what my teacher taught me, Im just mad at the stupid mark scheme which says otherwise. Maybe theres something related to it being in liquid form? because the term liquid was in bold.. anyway thanks for your help..

[Deadly_king]

Take an example of water, it is a polar molecule. The degree of polarisation varies, it is not the same always so it seems that these dipole forces must be breaking and forming all the time.

I agree with you here. These induced dipole forces are constantly being formed and broken. However it can't be stronger than the permanent dipoles

I totally agree with every word you said, thats what my textbook said and thats what my teacher taught me, Im just mad at the stupid mark scheme which says otherwise. Maybe theres something related to it being in liquid form? because the term liquid was in bold.. anyway thanks for your help..

Hmm..............HCl exists as H⁺ and Cl^- in the liquid form. Hence this is still permanent dipole forces between the positively charged H⁺ and the negatively charged Cl^-.

Anytime buddy.

[Master_Key]

I agree with you here. These induced dipole forces are constantly being formed and broken. However it can't be stronger than the permanent dipoles

Permanent dipole-dipole forces are more dominant in solids than in liquids. Take an example of Nylon, it is polar and so it attracts water even when it is not rubbed but water is only attracted to certain degree. This means that the permanent dipole force of nylon is greater. Yes the force of Permanent dipole-dipole is greater than induced dipole forces but the greatest is between sulphide bonds (S-S).

[Deadly_king]

Permanent dipole-dipole forces are more dominant in solids than in liquids. Take an example of Nylon, it is polar and so it attracts water even when it is not rubbed but water is only attracted to certain degree. This means that the permanent dipole force of nylon is greater. Yes the force of Permanent dipole-dipole is greater than induced dipole forces but the greatest is between sulphide bonds (S-S).

Yeah I know that buddy. But disulfide bonds occur only in protein.

Nylon cannot be compared to HCl since it is a polymer with much different structures.

Permanent-dipole is much stronger than induced dipole. Am sure about that.

[7d]

Post 'em all here!!!!

I do Edexcel AS chemistry!

hiii i need help on unit 1 energetics like hess's cycle
i kinda get it but i kinda don't
hehe thanks to anyone who can help
(would be great if you could give me some links)
thanks

[Deadly_king]

hiii i need help on unit 1 energetics like hess's cycle
i kinda get it but i kinda don't
hehe thanks to anyone who can help
(would be great if you could give me some links)
thanks

Try this for now. I'll keep adding some new sites.

[7d]

Try this for now. I'll keep adding some new sites.

thank you this should help xD

[Deadly_king]

thank you this should help xD

Anytime

Here is another one. Just in case.

[The Golden Girl =D]

Do I need to know the following equations :

http://www.chemguide.co.uk/organicprops/alkenes/dioleqn3.gif

http://www.chemguide.co.uk/organicprops/alkenes/dioleqn4.gif

http://www.chemguide.co.uk/organicprops/alkenes/dioleqn2.gif

If Yes then can you explain it Please :$ :S ?

Thank you in Advance

[Deadly_king]

Do I need to know the following equations :

http://www.chemguide.co.uk/organicprops/alkenes/dioleqn3.gif

http://www.chemguide.co.uk/organicprops/alkenes/dioleqn4.gif

http://www.chemguide.co.uk/organicprops/alkenes/dioleqn2.gif

If Yes then can you explain it Please :$ :S ?

Thank you in Advance

Well i don't know about EDEXCEL syllabus but for CIE, you need not know exactly everything about it.

This is about oxidation of alkenes. The latter can be oxidised both under cold and hot conditions but the mechanisms will vary.

You should just know that upon oxidation of alkenes with cold purple KMnO₄, a diol will be produced and the purple colour will disappear to give a colourless solution.

If K₂Cr₂O₇ is used as oxidising agent, then the colour change will be from orange to green.

However under hot conditions, colour change will be the same but the C=C will break and each will form compounds with respect to the other group of atoms the carbon is carrying.

If the carbon forming the C=C carries two hydrogen atoms, then carbon dioxide and water will be formed.

If the carbon carrying the C=C carries one hydrogen atom, then it will get oxidised to an aldehyde. If oxidation continues, the aldehyde will get further oxidised to a carboxylic acid.

If the carbon carrying the C=C carries no hydrogen atom, then a ketone will be formed.

Hope it helps

If you need any more clarifications, feel free to ask.

[The Golden Girl =D]

I didn't get the three last parts/ the last two images I posted :$

[Deadly_king]

I didn't get the three last parts/ the last two images I posted :$

The last one refers to oxidation under acidic conditions. This will make sure that the resulting mixture will be an acidic compounds.

The one before refers to oxidation under alkaline conditions which will form a salt of the compound.

Example : Ethanol + KMnO4 in NaOH -----> Sodium ethanoate + Mn²⁺

You need not know how to balance the KMnO4. You can just represent oxidation by [ O ] while reduction is replaced by [H] since it's quite complex to balance it. I don't think it's in the syllabus.

[The Golden Girl =D]

The last one refers to oxidation under acidic conditions. This will make sure that the resulting mixture will be an acidic compounds.

The one before refers to oxidation under alkaline conditions which will form a salt of the compound.

Example : Ethanol + KMnO4 in NaOH -----> Sodium ethanoate + Mn²⁺

You need not know how to balance the KMnO4. You can just represent oxidation by

• [/b] while reduction is replaced by [H] since it's quite complex to balance it. I don't think it's in the syllabus.
  

Okay wait ..... which last two did u refer to the one u talked about or the images I posted