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Physics paper 6 2012 + chemistry paper 2 2012 discussions

Messages
405
Reaction score
391
Points
63
need help :(
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w10_qp_31.pdf

last question last part..

nd how exactly do we find limiting reagent??
thnx :)
Moles of HCL = 40/1000 (convert cm^3 to dm^3)
0.04 * 2 as it says 2 Mol/dm^3, so 2 * 0.04 = 0.08 moles

Moles of CoCl2 = 0.08 / 2 = 0.04 [The ratio between HCl and CoCl2]
Number of moles of CoCl 2.6H2O formed = 0.04 [Same as above ^]
Maximum yield = 0.04 * 238 = 9.52

HCl = 0.08
Moles in 6g of CoCO3 = 6/119 = 0.050

Cobalt (II) Carbonate is in excess because the ratio was 1:2 (Between Cobalt and HCl)
And according to ratio cobalt's mole was 0.050 whereas HCl's was 2x0.04 (0.08)
As 0.05 is more than 0.04, Cobalt carbonate is in excess
 
Messages
65
Reaction score
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Points
28
No problem. Did you understand the explanation ? You see, HCl was limited and Carbonate ( i forgot the name ) was in excess, therefore HCl is the limiting reagent

actually its the carbonate in excess..nd thnx i got da explanation..
good luck
 
Messages
146
Reaction score
111
Points
53
Reaction
From
To
Alkenes and bromine water yellow/orange colourless
Alkanes and bromine water yellow/orange Remain yellow/orange
Chlorine with damp litmus blue Red then white/bleached
Hydrogen chloride – dry with blue litmus blue No change
Hydrogen chloride with damp blue litmus blue red
Hydrogen chloride in methylbenzene with dry litmus blue blue
Test for the presence of water – anhydrous copper sulphate white blue
Reaction of copper with concentrated nitric acid blue solution and brown fumes
Reaction of copper (II) salts with sodium hydroxide (test for Cu2+) blue solution and colourless solution light blue precipitate
Reaction of iron(II) salts with sodium hydroxide – test for Fe2+ green solution green precipitate
Reaction of iron(III) salts with sodium hydroxide – test for Fe3+ orange brown solution red brown precipitate
Sodium chloride + nitric acid + silver nitrate – test for Cl- colourless solutions white precipitate
Sodium bromide + nitric acid + silver nitrate – test for Br- colourless solutions pale cream precipitate
Sodium iodide + nitric acid + silver nitrate – test for I- colourless solutions yellow precipitate
Sulphate compounds and barium chloride colourless solutions white precipitate
Heating copper carbonate green solid black solid
Zinc or magnesium in copper sulphate solution grey metal in blue solution colourless solution and black solid
Magnesium burning forming magnesium oxide grey solid white solid
Colours of groups 1 and 2 compounds white solids colourless if dissolved in water
Hydrochloric acid and ammonia - neutralization colourless gases white solid
Chlorine water and sodium bromide solution colourless solutions yellow solution
Chlorine water and sodium iodide solution colourless solutions brown solution
Bromine water and sodium iodide solution colourless solutions brown solution
Heating hydrated copper sulphate blue solid white solid
 
Messages
146
Reaction score
111
Points
53
experiments u need to know
Section
experiments
1b​
1d​
Volume of 1 mole of hydrogen gas.doc
1e​
1i​
2b​
Reactions of alkali metals and water
2c​
  • Displacement reactions of halogens: Halogens experiment.doc
  • Dissolving hydrogen chloride in water and methyl benzene, halogens reacting with iron wool
2d​
  • Determination of the oxygen content of the air
  • Laboratory preparation of oxygen
  • Burning elements in oxygen
  • The thermal decomposition of copper (II) carbonate
2e​
  • Making hydrogen using metals and acids
  • Testing for water using anhydrous copper sulphate
2f​
  • Reactions of metals with acids
  • Displacement reactions of metals
  • Competition for oxygen between metals (e.g thermite reaction)
  • Causes and prevention of rusting
2g​
section 2g test for ions.pdf
3b​
Reaction of methane in the presence of UV
3c​
Testing for unsaturation using bromine water
3d​
4a​
4b​
4c​
4d​
5a​
5b​
5c​
Making nylon: Nylon.pdf
 
Messages
290
Reaction score
296
Points
73
Reaction

From

To

Alkenes and bromine water yellow/orange colourless
Alkanes and bromine water yellow/orange Remain yellow/orange
Chlorine with damp litmus blue Red then white/bleached
Hydrogen chloride – dry with blue litmus blue No change
Hydrogen chloride with damp blue litmus blue red
Hydrogen chloride in methylbenzene with dry litmus blue blue
Test for the presence of water – anhydrous copper sulphate white blue
Reaction of copper with concentrated nitric acid blue solution and brown fumes
Reaction of copper (II) salts with sodium hydroxide (test for Cu2+) blue solution and colourless solution light blue precipitate
Reaction of iron(II) salts with sodium hydroxide – test for Fe2+ green solution green precipitate
Reaction of iron(III) salts with sodium hydroxide – test for Fe3+ orange brown solution red brown precipitate
Sodium chloride + nitric acid + silver nitrate – test for Cl- colourless solutions white precipitate
Sodium bromide + nitric acid + silver nitrate – test for Br- colourless solutions pale cream precipitate
Sodium iodide + nitric acid + silver nitrate – test for I- colourless solutions yellow precipitate
Sulphate compounds and barium chloride colourless solutions white precipitate
Heating copper carbonate green solid black solid
Zinc or magnesium in copper sulphate solution grey metal in blue solution colourless solution and black solid
Magnesium burning forming magnesium oxide grey solid white solid
Colours of groups 1 and 2 compounds white solids colourless if dissolved in water
Hydrochloric acid and ammonia - neutralization colourless gases white solid
Chlorine water and sodium bromide solution colourless solutions yellow solution
Chlorine water and sodium iodide solution colourless solutions brown solution
Bromine water and sodium iodide solution colourless solutions brown solution
Heating hydrated copper sulphate blue solid white solid
yr dara Q rahay ho....??:cry:
 
Messages
146
Reaction score
111
Points
53
experiments u need to know

Section

experiments


1b


1d
Volume of 1 mole of hydrogen gas.doc

1e


1i


2b
Reactions of alkali metals and water

2c


  • Displacement reactions of halogens: Halogens experiment.doc
  • Dissolving hydrogen chloride in water and methyl benzene, halogens reacting with iron wool
2d


  • Determination of the oxygen content of the air
  • Laboratory preparation of oxygen
  • Burning elements in oxygen
  • The thermal decomposition of copper (II) carbonate
2e


  • Making hydrogen using metals and acids
  • Testing for water using anhydrous copper sulphate
2f


  • Reactions of metals with acids
  • Displacement reactions of metals
  • Competition for oxygen between metals (e.g thermite reaction)
  • Causes and prevention of rusting
2g
section 2g test for ions.pdf

3b
Reaction of methane in the presence of UV

3c
Testing for unsaturation using bromine water

3d


4a


4b


4c


4d


5a


5b


5c
Making nylon: Nylon.pdf
pass ur cursor on the text there are some links
 
Messages
290
Reaction score
296
Points
73
experiments u need to know

Section

experiments


1b


1d
Volume of 1 mole of hydrogen gas.doc

1e


1i


2b
Reactions of alkali metals and water

2c


  • Displacement reactions of halogens: Halogens experiment.doc
  • Dissolving hydrogen chloride in water and methyl benzene, halogens reacting with iron wool
2d


  • Determination of the oxygen content of the air
  • Laboratory preparation of oxygen
  • Burning elements in oxygen
  • The thermal decomposition of copper (II) carbonate
2e


  • Making hydrogen using metals and acids
  • Testing for water using anhydrous copper sulphate
2f


  • Reactions of metals with acids
  • Displacement reactions of metals
  • Competition for oxygen between metals (e.g thermite reaction)
  • Causes and prevention of rusting
2g
section 2g test for ions.pdf

3b
Reaction of methane in the presence of UV

3c
Testing for unsaturation using bromine water

3d


4a


4b


4c


4d


5a


5b


5c
Making nylon: Nylon.pdf
uuuuffffffffffffffffffffff.........ma gye....:eek:
 
Messages
146
Reaction score
111
Points
53
bunch of more chemistry notes (plz mention me in ur prayers)
 

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