Biology; Chemistry; Physics: Post your doubts here!

[funky brat]

Here ya go lassie

Cl2 + 2K+ + 2Br- ----> 2K+ + 2Cl- + Br2

We cut out 2k+ on both sides as kcl is also aqueous and we get the answer

So we don't inculde any aqeous product in ionic equations?

 

[funky brat]

Yes it is cream and white would be wrong,my sir penalised this

How do we learn colours, where did you learn them from?

 

[Faizan Muhammmad]

To white ghalat ho ga?
Yeh kahan se yad karnay hain phir?
All are compounds defined in the syllabus jin kay colours yad karnay hain?

I dunno, if it was correct or atleast large amount of candidates had done it would be written
The er says it can be cream or pale yellow, no white
what will we do ?

 

[funky brat]

Listen , dont worry about the makring schemes. Marking schemes are made after the papers are checked. White and Cream , there isnt much of a difference and alhamdolillah CIE is not THAT strict. They give us thori boht leniency.

Yes it is cream and white would be wrong,my sir penalised this

 

[funky brat]

Pa

I dunno, if it was correct or atleast large amount of candidates had done it would be written
The er says it can be cream or pale yellow, no white
what will we do ?

We'll cry maybe. asadalam help. :'(

 

[asadalam]

So we don't inculde any aqeous product in ionic equations?

Of aqueous we make ions like i made ions of K+ and Br- cuz they were in aqeuous form.

 

[Uchiha-Sasuke]

They are weird, I mean they say spectator ions do not take part when they are clearly.

I have the same problem :'(

Guys, I have problem with writing ionic equations, any tips?
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s08_qp_2.pdf
Like in B7 part a, I wrote K+(aq) Cl- (aq) = KCl (s) but they have written a different equation.
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s06_qp_2.pdf
Question 10 cii. :/

For Ionic equations:
1) Make equation
2) break into ions but dont break CO2 , H2O , Precipitate ( you'll have to learn which salts are insoluble in water) and elements e.g H2,Cl2, Mg, Na e.t.c
3) cancel out common ones
For this one :
Cl2 + KBr --> KCl + Br2
Cl2 + K+ Br- ---> K+ Cl- + Br2
Cl2 + Br- ---> Cl- + Br2
K+ is common which was cancelled
You know the reduction thing in the later part right ?

 

[Faizan Muhammmad]

Yes it is cream and white would be wrong,my sir penalised this

phir koee link ya page number bta

 

[asadalam]

1. Group 1, 2 metals are white/silvery white. Group 3 metals are shiny grey. Their compounds are white and their solutions are colourless.
2. Zinc is a grey solid, its compounds are white.
3. Lead is a shiny bluish metal, Iron is a shiny blackish solid.
4. Iron (II) salts are green. Iron (III) salts are red-brown.
5. Chlorine is a green gas. Silver chloride and Lead chloride are white.
6. Bromine is a red-brown gas. Silver bromide and Lead bromide are cream coloured.
7. Iodide is a black solid. Its vapours are purple. Silver iodide and lead iodide are yellow.
8. Copper is a pinkish solid. Copper (II) sulphate, Copper (II) hydroxide and Copper (II) nitrate are blue.
9. Copper (II) chloride and Copper (II) carbonate are green.
10. Nitrogen dioxide is a brown gas. Sulphur and Phosphorous are Yellow solids with different flames.

 

[ciesgetoveralready]

His Sir checked according to the marking scheme just like ecery other teacher. Cambridge kay examiners ki baat aur hai . Aisay thori ban gaye hain woh

 

[asadalam]

phir koee link ya page number bta

https://www.xtremepapers.com/community/threads/chemistry-atp-tips.25439/
Ye le

 

[Faizan Muhammmad]

my teacher said colours were dependant on positive only

 

[Faizan Muhammmad]

https://www.xtremepapers.com/community/threads/chemistry-atp-tips.25439/
Ye le

main bhee kahon itnee jaldee kaisay likh liay

 

[funky brat]

For Ionic equations:
1) Make equation
2) break into ions but dont break CO2 , H2O , Precipitate ( you'll have to learn which salts are insoluble in water) and elements e.g H2,Cl2, Mg, Na e.t.c
3) cancel out common ones
For this one :
Cl2 + KBr --> KCl + Br2
Cl2 + K+ Br- ---> K+ Cl- + Br2
Cl2 + Br- ---> Cl- + Br2
K+ is common which was cancelled
You know the reduction thing in the later part right ?

Yeah, I know that.
Thanks a lot, really did help.

 

[funky brat]

main bhee kahon itnee jaldee kaisay likh liay

Are you underestimating his typing speed?

 

[Faizan Muhammmad]

Are you underestimating his typing speed?

no overestimating the chappa speed
but very good points nevertheless

 

[funky brat]

1. Group 1, 2 metals are white/silvery white. Group 3 metals are shiny grey. Their compounds are white and their solutions are colourless.
2. Zinc is a grey solid, its compounds are white.
3. Lead is a shiny bluish metal, Iron is a shiny blackish solid.
4. Iron (II) salts are green. Iron (III) salts are red-brown.
5. Chlorine is a green gas. Silver chloride and Lead chloride are white.
6. Bromine is a red-brown gas. Silver bromide and Lead bromide are cream coloured.
7. Iodide is a black solid. Its vapours are purple. Silver iodide and lead iodide are yellow.
8. Copper is a pinkish solid. Copper (II) sulphate, Copper (II) hydroxide and Copper (II) nitrate are blue.
9. Copper (II) chloride and Copper (II) carbonate are green.
10. Nitrogen dioxide is a brown gas. Sulphur and Phosphorous are Yellow solids with different flames.

EDIT EDIT EDIT: Bromine is a liquid.

 

[Faizan Muhammmad]

and how is iron shiny and blackish at the same time?

 

[funky brat]

1. Group 1, 2 metals are white/silvery white. Group 3 metals are shiny grey. Their compounds are white and their solutions are colourless.
2. Zinc is a grey solid, its compounds are white.
3. Lead is a shiny bluish metal, Iron is a shiny blackish solid.
4. Iron (II) salts are green. Iron (III) salts are red-brown.
5. Chlorine is a green gas. Silver chloride and Lead chloride are white.
6. Bromine is a red-brown gas. Silver bromide and Lead bromide are cream coloured.
7. Iodide is a black solid. Its vapours are purple. Silver iodide and lead iodide are yellow.
8. Copper is a pinkish solid. Copper (II) sulphate, Copper (II) hydroxide and Copper (II) nitrate are blue.
9. Copper (II) chloride and Copper (II) carbonate are green.
10. Nitrogen dioxide is a brown gas. Sulphur and Phosphorous are Yellow solids with different flames.

Very helpful indeed.

 

[funky brat]

and how is iron shiny and blackish at the same time?

You never saw iron?