Chemistry doubts..ask here!

[cHeStEr]

Hey,

Danggggg...that took me an year to read! Alot of help tho!
Heres my doubt:

if copper oxide is reacted with hydrogen what would the colour change to?

M/J 2004 question (6)

BR,
Xenarra

It will give cu and water .. So .. Copper
Which would be reddish brown most probably !
Black which is cuo to cu reddish brown or brown
Good luck :good:

srry.... but copper is pink not reddish brown
so the colour change is from black to pink

http://en.wikipedia.org/wiki/Copper_(color)
Cross Check it !

 

[HorsePower]

i have a 2 questions
so why do we need to heat a metal oxide when making excess base method..why don't we heat with the other reactants?

and what is the difference between a test tube and a boiling tube

srry but i dont really get ur first question ... but we heat the solvent so that its solubility increases and it can dissolve more metal oxide and the metal oxide needs to be in excess to make sure all of the solvent has reacted ..
for the next question, well boiling tube and test tube look exactly the same but the only difference is that boiling tube is twice the size of a test and can resist more heat
hope that helps

 

[narutogirl]

Mhmm, I need help in ths paper : http://www.xtremepapers.me/CIE/Cambridg ... 8_qp_6.pdf

What will the results be in q5 c)iii) & d)iii) since both are not sulphates

Anyone willing to help me

for c)iii..there will be no reaction because HCL and BrCL i use my logic in saying they both have chloride so no way they would react ( i know its stupid but works )
d)iii) same thing..they just want to trick u

Hey .. Was I wrong ? .. If yes .. I better be studying !!
If i was .. Then sorry ! cozmo35d

hey sorry i was the one who is totally wrong..D:
i read the question wrong..so ya it is to test for sulfate and there was no sulfate..am so sorry :/

 

[HorsePower]

@ cHeStEr (i hope i got that right) : oh srry.... my bad
but i just checked the 'ms' and it says 'red/pink/brown' soooo we're both right

 

[Xenarra]

hey,

ok this is what i the format of the questions might be right? :

label apparatus
graph question
the big box with all the tests of ions and stuff
an experiment which ends with , how to make it more accurate
huge question on chromatography/other experiments
measuring cylinder readings question

BR,
xenarra

GOOD LUCK EVRYONE!!!

 

[Xenarra]

Hey,
if anyone still here, could you answer this:

Do we need to add activated charcoal to the phenolphthalein to get rid of it from the solution...like for example while making crystals.

BR,
xenarra

 

[ajmanutd]

hey,

ok this is what i the format of the questions might be right? :

label apparatus
graph question
the big box with all the tests of ions and stuff
an experiment which ends with , how to make it more accurate
huge question on chromatography/other experiments
measuring cylinder readings question

BR,
xenarra

GOOD LUCK EVRYONE!!!

yeah thatll b sumwat wat the question frmat wud b..
thanx

 

[cHeStEr]

@ cHeStEr (i hope i got that right) : oh srry.... my bad
but i just checked the 'ms' and it says 'red/pink/brown' soooo we're both right

Lol there was no pink there too !
Nvm it happens!

 

[lavanyamane]

Can you guys please tell me the colour changes of various indicators?
Methyl orange - acid, base, neutral?
Phenolphthalein - acid, base, neutral?
Any others?

methyl orange acidic: red
neutralrange
alkaline:yellow

phenolphthalein
acidic: colourless
neutral : colourless
alkalineink/purple

litmus paper
acidic:red
neutral:violet
alkaline:blue

that is wat is in my notes but i somehow feel they r kinda wrong :/

I know! Everywhere I look, there are different colours
Anyway I have my exam in 50 minutes, so no point fretting now.. Good luck! <3

 

[shan5674]

Hey for electrolysis of copper, is the the pure copper the anode or cathode?

 

[narutogirl]

Hey for electrolysis of copper, is the the pure copper the anode or cathode?

at the cathode

 

[shan5674]

Hey for electrolysis of copper, is the the pure copper the anode or cathode?

at the cathode

Thanks

 

[haochen]

hi im back

 

[shan5674]

hi im back

lol good

btw, what time do you do you exam? where r you?

 

[haochen]

im in jeddah and my exam start at 3 pm
and u???

 

[shan5674]

im in jeddah and my exam start at 3 pm
and u???

Im in Qatar and my exam starts at 3 pm too

you do variant 1 right?

 

[haochen]

yeah

 

[shan5674]

hey can u tell me how to draw the link for terylene, amide bond etc etc please

 

[xIshtar]

hey can u tell me how to draw the link for terylene, amide bond etc etc please

Wow, haven't ever seen it in paper six..

Basically, amine bond in amino acids etc is NH2 I believe, and the amide bond in polyamides is NHC=O, from the top of my head. I haven't gone over polymers in a while, it's been all about other subjects, but now it's chemistry time

 

[AStarHunter]

hey, i have a qs in this paper -->http://www.xtremepapers.me/CIE/Cambridge IGCSE/0620 - Chemistry/0620_w06_qp_6.pdf---> Q4(d)---> i drew a best fit straight line for eperiment 2 and a curve for experiment 3-- I am not sure if this is what i was supposed to do... anybody got any ideas ?