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Since the total mass is 160, how much does Sulphur contribute to it?
= 64 (Cu) + 32 ( S) + 16*4 (O2)
Therefore, sulphur contributes 32g of the total 160g.
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Since the total mass is 160, how much does Sulphur contribute to it?
Ohh thanx ! so this is da way !!!! Lolz!@@! JazakAllah@Since the total mass is 160, how much does Sulphur contribute to it?
= 64 (Cu) + 32 ( S) + 16*4 (O2)
Therefore, sulphur contributes 32g of the total 160g.
The main composition of dry air is nitrogen and oxygen.http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_11.pdf
Q31. Can anyone explain why it's B.
22-you must make hydarted crystals thus, you first need to filter off your solution and keep the residue which are the crystals. Then you will repeat the procedure of adding CuO to the acid as to concentrate the crystals. Then you will filter off again and will then wash the crystals. You cannot heat the crystals as the question clearly asks for Hydrated crystals. Heat will certainly remove the water giving anhydrous crystals. so teh correct order is 2-1-2-4http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s10_qp_11.pdf
Please explain me Q 22 and 26 !!
A chemical engineer plans to produce hydrochloric acid.
Which metal is best for the reaction container?
A copper
B iron
C magnesium
D zinc
Could someone please explain why the answer is A? :s
the metal must be less reactive than Hydrogen or else the acid will react with the metal meaning that hydrogen will be displaced by this reactive metal. So you must choose a less reactive metal, less reactive than hydrogen. Only copper is less reactive than hydrogen thus copper will not react with the acid to try and displace these hydrogen ions.
The reactivity series for metals is
K
Na
Ca
Mg
Al
C
Zn
Fe
Sn
Pb
H
Cu
Ag
Au
Pt
nah don't worry about it, and you're most welcomeOh my God I feel so stupid x_x
Thank you!
Variant?chemistry
w09 q#14
thank you !!22-you must make hydarted crystals thus, you first need to filter off your solution and keep the residue which are the crystals. Then you will repeat the procedure of adding CuO to the acid as to concentrate the crystals. Then you will filter off again and will then wash the crystals. You cannot heat the crystals as the question clearly asks for Hydrated crystals. Heat will certainly remove the water giving anhydrous crystals. so teh correct order is 2-1-2-4
26- A and B are eliminated directly as both chlorine and fluorine are more reactive than bromine so they aren't displaced thus no colour change is observed
for C, Fluoride ions are more reactive than chloride ions thus again no dsiplacement takes place and the solution doesnt change colour
Yet, for D , the correct answer, Chlorine is more reactive than iodine thus it will displace the iodide ions from the solution and will result into sodiumchloride and iodine. I2 which is iodine solution is red-brown in colour and this is what causes a dark colour to be formed from colourless to dark brown.
Variant?
Copper only reacts with nitric acid!why doesnt copper form copper(II) sulphate with warm dilute sulphuric acid?
no.26 , June2000.
no.20,June2002.
no.4,June2009.
no.4,June2010 .
Please some1 explain them .
The answer should be C..
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