Li, KCl

[wolfson]

1. I have looked at most of the sites (america) and NOT ONE says that Li is more active than K, istly Active means Reactive. 2ndly these sites just put the active elements in there groups, it may look as if Li is more active than K, but that is just because Li is above K in the periodic table of elements, YOU MUST learn that reactivity increases as you go down g1. I have attached a picture explaining it to you, FROM an AMERICAN site.

[JaKiri]

I don't like that diagram, as the horizontal arrow implies it continues for the nonmetals as well.

[MulderMan]

schools out! ive still got another month left!!oh well. ive not got a BSc but some/most people here have which is what most if not all teachers have anyway so i dont doubt alot. over here its compulsary chemistry knowladge to know the reactivity series in water and oxygen, before ya start GCSE's, but i dont know what year your in,

[YT2095]

thnx Wolfson

 

also it would be a good idea to a + sign in the bottom left hand corner of your periodic table, right next to Francium and a corresponding - sign in the top right hand corner next to Fluorine, it`ll give a rough indication on a sliding scale of electronegativity

 

another refference that you may wish to look up is the Pauling scale, that also clearly states that Li = 1.0 and K =0.8

the lower the number, the more electro-positive the element is

[wolfson]

Its a DEX diagram, the arrow is applied for metals only, it shows the rule thats all you need to know.

[JaKiri]

another refference that you may wish to look up is the Pauling scale' date=' that also clearly states that Li = 1.0 and K =0.8

the lower the number, the more electro-positive the element is [/quote']

 

based on the electronegativities (link[/url'])

 

It's like a tag team, but without any teamwork. Or tags.

[wolfson]

another refference that you may wish to look up is the Pauling scale, that also clearly states that Li = 1.0 and K =0.8

the lower the number, the more electro-positive the element is

 

Thats totally correct (hands clap) good reference YT

[JaKiri]

Its a DEX diagram, the arrow is applied for metals only, it shows the rule thats all you need to know.

 

I know what it is, but without additional text it can give the wrong impression.

[YT2095]

Jakari, also a good link, I didn`t have to use it though, I worked from Memory on that one, but yes, that does ALSO put it into clear facts, Thnx Jakiri

[wolfson]

I know what it is, but without additional text it can give the wrong impression.

 

Yes your right, typical american sites. Well one day ill get round to sorting it out, budullewraagh should also learn basic chemistry and non of this would have happened, oh well maybe we can teach him the English chemistry here

[YT2095]

well I must confess to being more than a little offended with this "It`s an English thing/problem" type of wording, but as a Moderator, I must restrain myself from reactionist behaviour, having said that, Damn Your Socks! Buddleythingy! )

[JaKiri]

I'm fine with it being 'English Chemistry', it just means we're several hundred years ahead of the rest of the world.

 

As if we needed any more proof.

[YT2095]

Well Yeah, there is also That way to look at it aswell )

[Dave]

Just goes to show the English are superior

[apathy]

OK, this discussion is STUPID!!!!

 

When talking about activity/reactivity it's all a relative thing.

 

If I were to take a chunk of lithium and chunk of potassium into my nitrogen filled glove box, then as for the metals reacting with the nitrogen LITHIUM wins, because lithium will react with the nitrogen to form LiN3, the potassium will not react at all.

 

If I then take a chunk of lithium and a chunk of potassium into an argon filled glove box and heat them both in the presence of graphite POTASSIUM wins, since at atm pressure lithium will not react with graphite, but potassium will to form C8K.

 

Thank you.

[apathy]

as for Li displacing K in KCl

 

are you talking about Li + KCl --> LiCl + K ?

Look up the standard reduction potentials

 

Li --> Li+ +3.040 V

 

K+ --> K -2.936 V

----------------------------

+0.104 V

 

 

It's positive, by god, and that means it's spontaneous (at STP).

So Li will displace K in KCl to form LiCl.

 

Also, look at the differences in lattice enthaply. LiCl is more stable.

KCl = 715 kJ/mol

LiCl = 853 kL/mol

 

Based on that (if you did this in an inert atm) then the reaction should go.

[YT2095]

I can hardly beleive you`re accepting and condoning this idea

need I say it again, Li will NEVER displace Potassium, no matter WHAT atmosphere you put it in, yes Li will make a nitride quite easily, it will also affect Glass, so no doubt some will think it`s like Fluorine now (

 

Apathy, tell me why, Sodium (between Li and K) won`t displace potassium? surely it`s a perfectly happy medium of the 2 elements, and yet it won`t either.

 

and btw, NaOH will also effect Glass, as will KOH

[budullewraagh]

sorry to say this, but you're WRONG. first, i asked a retired chemist i know. he agreed with me. i can back that statement up because if you look at the standard reduction potentials of alkali metals you will notice that Li is harder to reduce than K. that's how he explained it. also, check the effective nuclear charges.

[apathy]

Lithium has the lowest standard reduction potential in the periodic table. This is not equivalent to first ionization energy, where cesium has the lowest.

 

Sodium won't displace potassium because it's standard reduction potential is HIGHER than potassium's.

 

Li = -3.040 V

Na = -2.713 V

K = -2.925 V

Rb = -2.924 V

Cs = -2.923 V

 

Look up a table of reduction potentials. You will see that it does not follow a periodic trend all the time.

 

And you'd better do it under argon or helium, because the metals will react with the air. You can't do it under cheap ole nitrogen because of the LiN3 thing.

 

edit: hehe switched up the highests with the lowests

[apathy]

what the hell do base baths have to do with anything?

[budullewraagh]

And you'd better do it under argon or helium, because the metals will react with the air. You can't do it under cheap ole nitrogen because of the LiN3 thing.

since i cannot obtain those, i'll be doing it in a nonpolar liquid like an oil.

 

by the way, thank you for your support.

[budullewraagh]

also, i would like to add that when mixed with H2O, alkali metals tend to form oxides rather than hydroxides. H2 tends to be released

[apathy]

oh, yeah, mineral oil will work (avoid silicone oil)

 

but, even though H2 is given off , the oxides still hydrolyze to hydroxides

[budullewraagh]

depending on the amount of the alkali metal there will be more or less hydroxides...

[Mr_Mediocre]

G'day All, newcomer here...just thought I'd put in my 2 cents on this one.

 

I Don't want to be presumtuous, but I think you might be barking up the wrong tree(s). If you look in your SI data books you'll find the aqueous solubilities of Li2CO3 and K2CO3...

Actually, dont worry about it, i'll tell you Li2CO3 = 1.33 g/100ml, K2CO3 = 112 g/100ml.

 

If you dissolve your KCl in water (solubility of 34 g/100ml, so use about 15 g in 100 ml), add Na2CO3 (solubility of 21 g/100ml, so use about 10g) (or even NaHCO3 with some sodium hydroxide to bring the pH up) as your carbonate source (don't be afraid to warm it a little). Then add your LiCl (solubility 83 g/100ml) you will get Li2CO3 precipitating from solution as you progressively add your lithium salt.

 

If it is specifically LiCl your are after, then dissolve the Li2CO3 in HCl (fairly conc. add SLOWLY, NO HEAT) and reduce volume to get your nice LiCl crystals...

 

Hope this works for you,

 

Cheers