hi. I was wondering does anyone have any good notes on salt preparation? Or can you please explain it to me? (all the methods and such) Also..this is going to sound really stupid but can anyone be bothered to put together a list of compounds and their colours (the one's required?) I have a couple of them but I'm not sure if they're a)needed and b) correct.
Thank you. Oh and if it helps I'll post the list of the colours I DO know so you can just tell me the one's I'm missing out or the ones which I've got wrong.
Here it is:
1. CuCO3 ===>Green
2. CuO ===> Black
3. CuSO4 ===>White
4. CuSO4.5H2O ===> Blue
5. CoCl2.6H2O ===> Pink
6. CoCl2 ===> Blue
7. MnO2 ===> Shiny Black
8. KMnO4 ===> Purple
9. K2Cr2O7 ===> Orange
10. CuCl2 ===> Blue
Again, Thank you help will be much appreciated. ^^
hi, there are 4 ways of making salts ill explain to u all of them
a) to make inoluble salts(barium sulphate):1) take 2 soluble forms of the chemical used to make barium sulphate, eg:barium nitrate and sulphuric acid
2) add barium nitrate to sulphuric acid then filter the mixture
3)u will get the residue(the insoluble part,i.e barium sulphate) and the filterate (of whats left of the liquid part)
4) wash those crystals of barium sulphate with distilled water and dry them using 2 filter papers(this avoides the braking of crystals) and finally u got clear barium sulphate.
b) to make salts from very reactive metals (eg, sodium, pottasium or any of the first 3 metals in the reactivity series)1)lets say we want to make sodium chloride(NaCl, or table salt).such process where making salts with reactive metals are done with and experiment called TITRATION.alright now u will need burette and pippete.its usually done with appropriate alkali (eg for this one sodium hydroxide(NaOH)) with an apropriate acid(eg for this one hydrochloric acid (HCl)) this is called NEUTRALISATION where alkalis react with acid to from salt and water.
2) FROM THE PIPPETE pour some unkown amount of sodium hydroxide to a conical flask
3)add an indicator pheonolphthalein which turns pink in colur when in alkali.
4)using burette pour out the acid hydochloric acid, keep doin tht untill tht pink colour dissapers.
5)then pour out every thing from the conical flask, repeat the experiment with the same amount of the alkaline and with out using the indicator, this is done because the indicator present makes the salt impure.
6)bring the above colourless solution in a china dish and evaporate it untill crystalls apear
then filter the crystals out and washed them with distilled water and dry them between 2 filter papers.
and u finally get pure sodium chloride.
c)to make salts from weak metals(magnesium to tin in the reactivity series)1)lets say u want to make magnisium nitrate. do u remeber thos question i paper 6 where they say add in excess? this is the process of making salts with weak metals by adding things in excess.Alright now what we need is magnesium and an acid nitric acid.
2)take in a beaker nitric acid and add magnesium in excess to it, u will see effervecense appear due to liberation of oxygen. wait until the effervescence end. u will see excess pices of magnesium carbonate.
3)filter the mixture,to get the SOLUTION of magnesium ntrate , which is the filterate
4)take the filterate to a china dish, and evaporate to crystallisation point and then cool slowly till crystals are formed.
5)collect crystals again by filteration.wash it and dry it with filter papers.
d)to make salts from very week metals(eg copper nitrate)1)alright this would be same as the above procedueres. take an acid like nitric acid, and take some amount of coper oxide.
2) pour some amount of nitric acid to the beaker and add excess copper oxide and warm it
3)now there wont be any effervecence here cuz the product of this reaction would be copper nitrate and water and no gas so no effervescence
4)filter the mixture, take the crystals and wash it and dry it as usually.
thts all for making salt.now the colours are alright, but rmember tht all oxides of group 1 and 2 metals are white in colour and oxides of transition are colourfull i think, but mostly its black.
ell any consufion or difficluties, or help u need plz do ask.
and plz + rep me, if everythings allright with my explanaition.hope u understand.
