Chemistry doubts..ask here!

[haochen]

hey can some one give me the name of a solvent that can be used for chromatography pleasee

if they ask for ink .... use water
but if the ask for the pigment in leave(chlorophyll) DONT USE WATER, USE ETHANOL
because if chlorophyll dissolve in water, when it rain all plant will be white

hope it helped

 

[narutogirl]

well i would really like to help you and haochen did already but i got myself confused, because it all depends on the question...because i know if we keep the same volume but different conc. the rate will differ but the same product
about the second question..i don't really know..i kinda didn't understand the question
so if it is in a pastpaper..tell me and i will check it out and i could understand more

 

[xIshtar]

well i would really like to help you and haochen did already but i got myself confused, because it all depends on the question...because i know if we keep the same volume but different conc. the rate will differ but the same product
about the second question..i don't really know..i kinda didn't understand the question
so if it is in a pastpaper..tell me and i will check it out and i could understand more

http://www.xtremepapers.me/CIE/Cambridg ... _qp_61.pdf
Question 4.(d)
I understand myself now, sorry I confused you

 

[omartwee]

Thanks for the notes
Hopefully Chemistry Paper 6 will be a good one..

I have a couple of questions which I hoped you could answer...
If you half the concentration, but use the same volume as before, half the product will be produced right?
If you half the amount that you are dissolving, the temperature change will fall, as it is less saturated...
What will happen to the rate of reaction in this case though?
If you double the volume of solvent used, will this cause a slower or faster rate of reaction?

if u double the solid then temp will rise by double.
if u double the liquid then the temp will decrease by half.(because more water molecule ids present so it absorb the heat)
if half the concentration is used, half the product (as u said )
if concentration doubled the rate of reaction will also increase





hope that helped

Thanks, you helped a lot.. What would the overall effect on the rate of reaction be though. With a lower temperature would it not mean a slower rate?

sorry i just wanted to ask if you are sure that the product will be halved if the concentration is halved?!

 

[narutogirl]

well i would really like to help you and haochen did already but i got myself confused, because it all depends on the question...because i know if we keep the same volume but different conc. the rate will differ but the same product
about the second question..i don't really know..i kinda didn't understand the question
so if it is in a pastpaper..tell me and i will check it out and i could understand more

http://www.xtremepapers.me/CIE/Cambridg ... _qp_61.pdf
Question 4.(d)
I understand myself now, sorry I confused you

ya i got it now..lol
but for ur first question..isn't it the same product because concentration affects the rate of the reaction but the volume determines the product..?

 

[haochen]

btw where do u live narutogirl ???
when u posted ur e mail i checked in facebook and u are already my friend (dunno when i added u )
and ur in jeddah ????!!!!

 

[haochen]

sorry i just wanted to ask if you are sure that the product will be halved if the concentration is halved?!

yeah because less concentration so less molecule so less product

hope u got it

 

[shan5674]

hey can some one give me the name of a solvent that can be used for chromatography pleasee

if they ask for ink .... use water
but if the ask for the pigment in leave(chlorophyll) DONT USE WATER, USE ETHANOL
because if chlorophyll dissolve in water, when it rain all plant will be white

hope it helped

heyy thanks aloot

 

[lavanyamane]

http://www.xtremepapers.me/CIE/Cambridg ... _qp_61.pdf
Q. 7?

 

[haochen]

ur welcm

 

[angel786]

hye
can any 1 tell me about tritation methods????

 

[shan5674]

Test for alcohol? :S

 

[haochen]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_s10_qp_61.pdf
Q. 7?

it is general chmistry

first u use a mortar and pestle and crush it , to increase surface area.
then u add an acid eg. HCl and the dissolve it
and now copper carbonate react with hydrochloric acid to form copper chloride and CO2 and Water
then copper chloride (think think think) u can use displacement reaction to get copper
as the question said copper is the least reactive metal u can use add metal eg. magnesium(coz it is more reactive)
so react copper chloride with magnesium to form magnesium chloride and copper
and then filter copper through filter funnel and u got the copper

it is easy when u use a little of your knowledge


hope u got it

 

[haochen]

Test for alcohol? :S

use potassium manganate
it will turn from purple to colorless

use potassium dichromate
it will change from orange to green

use:
it is use by the police to test if the driver have drank alcohol when driving.

hope u got it

 

[narutogirl]

btw where do u live narutogirl ???
when u posted ur e mail i checked in facebook and u are already my friend (dunno when i added u )
and ur in jeddah ????!!!!

hey..this is weird..really weird...
ya i had this account on facebook years ago because i wanted an extra friend in pet society so i made an extra account..lol and i added ppl who had ones and anime fans n i guess i added u..lol i didn't know abt igcse back then..lol XD
ya i am in jeddah

 

[haochen]

hye
can any 1 tell me about tritation methods????

it is when u react a base with and acid to form salt and water.

do u need the steps ?????

 

[shan5674]

hye
can any 1 tell me about tritation methods????

Theres just one method of titration i guess and that is:

for example lets say u want to titrate HCl with NaOH:

1-Fill NaOH into a burette
2-Measure a certain volume of HCl solution and transfer that into a conical flask
3-Add a few drops of phenolphthalein(indicator solution) into the conical flask
4-Carefully add HCl from the burette into the conical flask until you get a permanent pink colour
5-Record the final reading on the burette
6-repeat without the indicator (phenolphthalein)

Correct me people

 

[narutogirl]

sorry i just wanted to ask if you are sure that the product will be halved if the concentration is halved?!

yeah because less concentration so less molecule so less product

hope u got it

are u sure because i remember when doing graphs and they differ the concentration..the one with less conc..will be less steep but will end at the same volume of the first reaction indicating that the rate will differ but not the product it self :/

 

[shan5674]

Test for alcohol? :S

use potassium manganate
it will turn from purple to colorless

use potassium dichromate
it will change from orange to green

use:
it is use by the police to test if the driver have drank alcohol when driving.

hope u got it

Thank you

 

[haochen]

btw where do u live narutogirl ???
when u posted ur e mail i checked in facebook and u are already my friend (dunno when i added u )
and ur in jeddah ????!!!!

hey..this is weird..really weird...
ya i had this account on facebook years ago because i wanted an extra friend in pet society so i made an extra account..lol and i added ppl who had ones and anime fans n i guess i added u..lol i didn't know abt igcse back then..lol XD
ya i am in jeddah

ohhh
i dont play it anymore (boooring )
from where r u ???