[omid (OP)]

Yesterday in omid's chemistry class omid learned from her teacher that metalloids don't form ions but when omid asked how come? teacher said  becasue it can't and that's it.


but what omid wana know is that if matalloids react with other metals and non metals then what are formed if neither an anion nor a cation? [] [] []

[Bored chemist]

The simple answer is that these elements tend to form covalent bonds.
The reason is that they have relatively high ionisation potentials and low electron affinities. (Some of the ionisation potentials are not all that high, but the ions formed would be quite big so they wouldn't pack closely into an ionic lattice. That makes it difficult to offset the energy needed to ionise the element against the crystal lattice energy)

[omid (OP)]

when a ionic bond is formed ions are produced but what are produced when covelent bonds are formed?  []

[Bored chemist]

Molecules.

[omid (OP)]

Molecules.

But ionic bonds also form  molecules

[Bored chemist]

Good point, but actually they generally form lattices.
It's dificult to show someone a molecule of, for example, sodium chloride. you can get a crystal of it but that's a collection of lots of ions.
On the other hand if I get some nicely crystaline carbon I can actually show you a single molecule.
Here is a picture of some molecules I would like for Xmas.
http://en.wikipedia.org/wiki/File:Cullinanroughpieces.jpg

[omid (OP)]

omid's chemistry book says
"the energy released form the combustion of 1 cm3 of liquid hydrogen is four times less then that of petrol. however the energy per gram is higher than other fuels, so liquid hydrogen is used as fuel in the booster rockets of the space shuttle"

Can you please tell omid what it really want to mention specially the bold parts []

[lightarrow]

omid's chemistry book says
"the energy released form the combustion of 1 cm3 of liquid hydrogen is four times less then that of petrol. however the energy per gram is higher than other fuels, so liquid hydrogen is used as fuel in the booster rockets of the space shuttle"

Can you please tell omid what it really want to mention specially the bold parts []

It means that you use preferably hydrogen in a rocket because you don't want to waste fuel just to lift it.

[omid (OP)]

omid had an exam on friday a chemistry practical exam.
it was to make a salt and calculate the %age yeild (ammonium nitrate (II)sulfate)
But the results for calculations'll be available on monday,  by the end of Experiment omid had some greenish liquid which is ment to form crystalls.
What type of crystals should omid expect to be formed if the experiment was all OK?

[Bored chemist]

I'd need a bit more information than that.
What did you add to what?

[omid (OP)]

I'd need a bit more information than that.
What did you add to what?

omid used the equation below;
(NH4)2SO4 + FeSO4 FORMS (NH4)2SO4.FeSO4.6H2O

enough or need more? []

[Bored chemist]

I think that if I did a search on the chemical formula of the product I would be able to find out a couple of things about it like the colour and perhaps a name (or two) for it.
What are you hoping to find out?

[omid (OP)]

I think that if I did a search on the chemical formula of the product I would be able to find out a couple of things about it like the colour and perhaps a name (or two) for it.
What are you hoping to find out?

While we all were done with the experiment all of omid's clasmates thought that omid is gona get the best results after looking at the product that is kept for crystalisation.
but the problem is that where we were suposed to test the solution (in the middle of experiment)on a red litmus paper omid's litmus paper didn't turned blue that why omid is wondering if her crystals will form or not?

[Bored chemist]

It's the nature of science that you dont really know what will happen until you have finished.

[omid (OP)]

It's the nature of science that you dont really know what will happen until you have finished.

Sorry BORED chemist but it didn't answer omid's question  []

[lightarrow]

I'd need a bit more information than that.
What did you add to what?

omid used the equation below;
(NH4)2SO4 + FeSO4 FORMS (NH4)2SO4.FeSO4.6H2O

enough or need more? []

Look for Mohr salt.

[omid (OP)]

Look for Mohr salt.

omid had some very Dirty and nasty [] crystals but omid's yeild was about 92%
so omid guess omid didn't go very wrong []