Chemistry doubts..ask here!

[haochen]

when concentration increase more product will be produced
when temp. increase it shift to the endothermic side (vise versa)
when pressure increase it shift to the low mole side (vise versa)

hope u understand

 

[ajmanutd]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_s05_qp_6.pdf...................in question 7 a ///will i draw the straight line leaving the point at ph 5.......any other things i need to consider while dealing with graphs....plz help.....what is best line of fit....when i have to draw freehand??????????...plz plz plz help

no u dont draw a line through pH 5 cz dat point is wrong or inaccurate..
line of best fit is a line which approximately leaves an equal no. of points above and below it..
they ask u wen they want u 2 draw a smooth curve which is drawn freehand..

hope it helped..

 

[shan5674]

when concentration increase more product will be produced
when temp. increase it shift to the endothermic side (vise versa)
when pressure increase it shift to the low mole side (vise versa)

hope u understand

okay i know this question may sound really silly but as i said before i just dont get chemistry so anyways:

how do i know which side is endothermic and which side is exothermic?
and which side has more moles and which side has less?

 

[haochen]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_w10_qp_63.pdf
Question 3 (d) Here the answer is the graph level will be higher than the original one but will not level up same at the end.
But in some questions in mark scheme they say that the graph should level up at the end after being steeper at the start and i dont understand when the graph should level up at the end and when should it rise higher without levelling up
This is the problem and i am really confused

in this question the said magnesium powder so think think think
magnesium powder increases the rate of reaction so the time taken will be less
and they said same mass so same product will be produced
so the graph will finish earlier (less time taken to finish the reaction coz it is in powdered)
with the same end (same mass of magnesium )

hope u understand

find more graph question so u can clear ur doubt

 

[haochen]

when concentration increase more product will be produced
when temp. increase it shift to the endothermic side (vise versa)
when pressure increase it shift to the low mole side (vise versa)

hope u understand

okay i know this question may sound really silly but as i said before i just dont get chemistry so anyways:

how do i know which side is endothermic and which side is exothermic?
and which side has more moles and which side has less?

if the forward reaction (arrow to the right ) releases heat it is exothermic
if the forward reaction reduces heat it is endothermic
(usually it is given in the question or with the equation)

mole are the number in front if the symbol.
eg. 2Cl have 2 mole
so count the mole of the symbol at the right and left and use the rule
remember never count or add the number inside or between the symbol

hope u got it

 

[shan5674]

when concentration increase more product will be produced
when temp. increase it shift to the endothermic side (vise versa)
when pressure increase it shift to the low mole side (vise versa)

hope u understand

okay i know this question may sound really silly but as i said before i just dont get chemistry so anyways:

how do i know which side is endothermic and which side is exothermic?
and which side has more moles and which side has less?

if the forward reaction (arrow to the right ) releases heat it is exothermic
if the forward reaction reduces heat it is endothermic
(usually it is given in the question or with the equation)

mole are the number in front if the symbol.
eg. 2Cl have 2 mole
so count the mole of the symbol at the right and left and use the rule
remember never count or add the number inside or between the symbol

hope u got it

lol yupp thank youuu :Yahoo!:

 

[mumudodo]

do we need ot focus on preparation of salts?
thanks.

 

[HyDraZin3]

Sorry to ask again :sorry:
http://www.xtremepapers.me/CIE/Cambridg ... 3_qp_6.pdf
Here in question 2 (d) (ii) the graph will level up at the end right?

 

[haochen]

ur welcm

 

[Romani2011]

Guys remember these colours for compounds:
- Copper(II)oxide: black
- Copper(II)carbonate: green
- Copper(II)sulphate: blue
- Lead(II)iodide: yellow
- Iron(II)chloride: green
- Iron(III)chloride: reddish-brown

And here are some flame tests for these metal compounds:
1)Sodium (ex: NaCl): green-yellow flame
2)Potassium (ex: KCl): lilac colour
3)Magnesium: bright-white light
4)Calcium: brick-red
5)Copper: green

And remember going down Group (I) metals: reactivity increases, fixed points decrease, size increases, and density increases.
going down group (II) is the same as going down group (I).
going down group (VII): reactivity decreases, fixed points increase, forces of attraction between particles increase.

 

[shan5674]

Sorry to ask again :sorry:
http://www.xtremepapers.me/CIE/Cambridg ... 3_qp_6.pdf
Here in question 2 (d) (ii) the graph will level up at the end right?

Nope it wouldn't level out in the end as the reaction is faster since the temperature has increased but the masses and products are still the same so im thinking the graph would be steeper but will end before the original graph, i.e, below the graph.

 

[haochen]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_s06_qp_6.pdf
Okat so question 3d
i dont understand what they mean by draw two striaght lines, one foe increasing and one decreasing temps. ?? :?
Im really confuzed!
Thanks in advance

if u plotted he point u will notice that it is like the shape of a mountain
but u use ur ruler and draw a straight line from the start point (increasing)
go even further than the last point
do the same with the other 3 point the u should get a interception at 52 (about)

then answer the further question

hope u got it

Sorry to ask again :sorry:
http://www.xtremepapers.me/CIE/Cambridg ... 3_qp_6.pdf
Here in question 2 (d) (ii) the graph will level up at the end right?

no problem im here to help

this question was a bit tricky (the graph should be going down) coz
u dont start off from the same point because when u increase the temp.
the time taken is less so u dont go off and join the point
u draw a line and touch the same volume line not the point

i think u wont under stand so ill try to post a pic

 

[shan5674]

Sorry to ask again :sorry:
http://www.xtremepapers.me/CIE/Cambridg ... 3_qp_6.pdf
Here in question 2 (d) (ii) the graph will level up at the end right?

no problem im here to help

this question was a bit tricky (the graph should be going down) coz
u dont start off from the same point because when u increase the temp.
the time taken is less so u dont go off and join the point
u draw a line and touch the same volume line not the point

i think u wont under stand so ill try to post a pic

So what i posted previously is wrong? :S the one replying to her post.

 

[haochen]

some are corrrect
ill try t post a pic of it

 

[ajmanutd]

best of luck every1 fr d exam tom.. :good: :good:
hopefully d paper will be easy and every1 will gt an a*...

 

[haochen]

hope u got it

 

[HyDraZin3]

k,Thnx a lot

 

[shan5674]

Thanks

Identify substances and assess their purity from
melting point and boiling point information - that was from the syllabus. Can u explain to me how you do that?

 

[haochen]

ur welcm

what i understand from u is u want what happen to the substance when impurity is added ???

then when impurity is added it decrease the melting point of the substance and increase the boiling point of the substance
it is alwayz (RULE)

to identify if water is pure
boil it and it will eveporate exactly at 100'C if it is pure

hope im right

 

[haochen]

best of luck every1 fr d exam tom.. :good: :good:
hopefully d paper will be easy and every1 will gt an a*...

thx u too