ChemSiddiqui

18 years

Tnx

it`s bond angle is not linear like CO2, it`s bent like H2O, the bond angle is 92 degrees

So wouldn't it make its shape trigonal?

Hi,

I was going through some of the exam papers when I saw that H2S (hydrogen Sulphide) has a linear shape. I wondered that when 2 of the 6 electron on sulphur bind to 2 hydogen ones to make a bond, it leaves 4 electrons on sulphur which makes it 2 lone pair. The shape the mark scheme says is linear. I was wondering does the 2 lone-pairs of electron cancel each other effect in terms of repulsion because otherwise H2S should have had a trigonal shape.

help out. Thnx

Hi,

does any 1 in SFN knows any website or link which would offer a good and easy way to learn german. And it should be free 2. any help appreciated.

didn't no where 2 post it so I thought its the place

quick Chemistry questions

 

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1) What type of chemical liaison must be present in an electrolyte? Give your reasons.

I am not sure about that. I think there isn't any binding needed for electrolyte. its just that it must conduct electricity.

2) How come ionic solids don't conduct electricity, but are good conductors after their fusion?

Ionic solids have very strong attractive forces b/w them. The electrons in them aren't free. But when you heat them and heat them enough to make them molten(fused) they strong attrative forces are broken and the ions are formed which ultimately conduct electricity.

Please try to do some reading yourself before you try to ask these sort of questions.

There is no specific method to do that really. Just try to add all the atoms of individual elements from each sides and balance it such that both sides would have same number of atoms of each individual elements. I can't however stress enough to practice and practice as much as you possibly can unless you feel confident to balance any equations!

embedded would be the same as sunk in.

Got that wrong i think in haste

Hi,

I was studying electrochemistry and in the text was a mention of 'adsorbtion'. I try my best to make matter as simple as possible for Juniors who approach me to ask chemistry related problems. So I came up with how best I can describe Adsorbtion to the junoirs if they approach me for it. I would like to share it with you:

" If we allow a snail to walk over a tennis ball the size of a football, it would leave its traces with look like a gel like structure. We say that the gel like structure have been adsorbed over the surface of the tennis ball i.e. embeded not sunk in"

Please leave your comment about how accurate this explaination is. I am open to criticism and I would appreciate any1 who points out the error.

Thnx

Well I thought it will be fun. Here goes:

"Look at the usernames of the members and try to guess/describe their physical appearance with you think will go with their name. Choose at least one member"

For a starter. Phi for All : Bulky heavy fella, bald and cheerful.

I wouldn't think there is any method except trying to balance the numbers of atoms of each individial element on both sides. The best thing however is to practice and practice. Good Luck!

Or maybe beause the Indian recognised Lord Moutbatten as their Governal-General(president those times) because he was Gandhi's friend but Pakistan refused to do so. So in return britishers supported India by allowing them to keep Kolkata and other fertile lands and to give Gandhi more publicity as a true 'leader'. But some historians like Stanely Wolpert and some others too realise that Jinnah as been unfairly forgotten and not publicised.

Jinnah and Gandhi are very well known across the world as the leaders who freed indians from the reiging British. Gandhi had a part to play so did Jinnah and a lot of other leaders. Jinnah got Indian freed from Britishers (along with Gandhi and others) but he also managed to separate the Muslims who felt inferior living with Hindus (history says I don't however I understand Hindu historian would say the opposite). I want you to decide on this debate whose topic I say shall be : "Why Gandhi is more famous than Jinnah".

Please take this debate lighlty, no hard feeling or offence involved.

Hi all,

I was asked this question which made me 2 think a lot. I will share it with you and want your take on it.

" Zinc and Copper are d-block elements with atomic radius measured in nanometres are 0.125 and 0.117 repectively. The data booklet I have got says that the first ionisation energy of zinc is +908 KJ/mol while copper's is +745 KJ/mol. Question is why zinc has a higher ionsation energy than copper when it size is larger than of cooper(slightly at least)"

So what I have got for answer was this:

Zn = [Ar] 3d10 4s2

Cu = [Ar] 3d10 4s1

Zn and Cu both have their valence electron in 4th shell and they are sheilded by equal no of electron in both cases. We know that atomic radius decreases across the period because of the increase in the nuclear charge and no sheilding effect(not very effective i mean). One reason I see for higher ionisation energy of zinc is that its nuclear charge is more positive due to increase in the number of protons. But I fail to understand why zinc atomic radius is larger than copper. 2 questions:

1. Is the question right ( i mean does it make sense)?

2. Your comments on my reasoning above.

Any help most appreciated:-) .

Thnx 4 that but from your answer of '3' say the ion is S-2, then should we divide the answer by 2, is it?

Hi, I have a few questions which I need u ppl to answer.

1. Its so confusing sometimes when you read books about which orbital is filled first 3d or 4s in d-block elements. I think since 4s has lesser energy so it is filled first. Is it correct or it is only a rule when writing electronic cofiguration?

2. I have come across with 'Group IIIA' or 'IVB" what does A and B mean here?

3. This one came in one the other forums I recently joined and there was this questions. I am going to present my answer to you but I need help. So here it goes:

"Given that on mole of particles is exactly 6.02 x 10^23 particles, deduce:

(a)the number of electrons required to convert 3.21g of sulphur into sulphide ions"

Now my take on it that: we will first of all divide 3.21 with 32 to get the number of moles of sulphur. we will then multiply the answer with the avogadro number to get the number of electrons required. What to do next????????????? or is it the answer.

Any help is most appreciated

Hi all,

I have read alot about acid-base titration in books and whenever I come across this topic I have observed that in titration reaction the volume of acid is taken to be less than that of an alkali.I have 2 questions.

1.Is my observation correct or not?

2. If so what is the reason for the said observation?

Any help will be most appreciated by me as always!!!!

Thnx alot testo! Cheers!

thnx 4 the help. I shall do as u say. I understand the terms you highlighted but wanted a broad yet easy explaination. But, hey thnx again.

agentchange thnx for them, I have tried wikipedia before. It is my first choice evertime I search for anything regarding chemistry. Have you or any1 else got a different link. Seriously, Google is of no help in this matter.

thnx anyway

Hi,

Can someone explain 'Inert Pair Effect' to me. It is not in A'levels syllabus but is important in understading the stabilities of Group IV element. I have read all the books I have and got nothing out of it.

You can provide links that could explain it easily, if you like.

Thnxx

Hi, I just read Group IV today and was surprised to know that Carbon melting point was higher than that of lead or tin. The explaination the book gave was that the giant covalent bonding in carbon doesn't allow the electron to move and thus it requires greater energy to separate the bonds and melt carbon. While metallic bonding shown by tin or lead is weak.

the idea didn't sink in. Can any 1 help.

Hi, I have some questions please answer them for me:

which is true about catalyst;

A. They lower the activation energy for a reaction

OR

B. They provide a different pathway, one with lower activation energy.

Now some books say the former but my teacher believes the latter is actually true. What is your say on it.

The below is a worked example from a book which I think has mistakenly printed it. what you say:

"

What is the pH of 2 mol dm-3 NaOH?

NaOh is a strong base, so it exists as ions.

So [OH] = [NaOH] = 2 mol dm-3

so -log[OH] = -log2

so pOH = - 0.3

so pH = 14 - (-0.3) = 14.3 "

Now how can the pH of anything be 14.3.

please help out in the above situations. thnx

Hi, I am preparing for interview at oxford for chemistry undergraduate chemistry course (MCHEM). I am looking for some tricky questions that might help me to enhance my understanding regarding different chemistry questions. If any1 of you has links to any website which have questions which can particularly help me in my chemistry interview I would be grateful if u provide me with that. And i have a question i need help in. it came as oxford university interview question:

"calculate the average interatomic spacings particles in the room". any help:confused:

Hi,

I was asked this question by my friend and when I gave away my answer he was unconvinced. So I ask you whether I was right or not.

He asked me what was the actual meaning of 'End-Point' when you do titration. I said that it is meant to be the end of reaction indicator. He argued that if that was the case then when we do neutralisation using a strong alkali and a weak acid then why the graph of that reaction shows that the end-point(in terms of ph) might have reached at ph9.

I was so confused about it that i told him that end-point does not necessarily means to reach a certain ph which might indicate us that the reaction has completed. I told him if he'd done a redox titration then ph was out of the question. But, still he looked unsatisfied.

All I ask is can any 1 tell me how to best define endpoint and when we do a titration of a strong alkali with a weak acid, maybe use a buffer as well then how can we find the endpoint in the graph for that reaction(titration).

Anyhelp will b appreciated