Chemistry Paper 61

[Patum]

I
WRONG, I wrote chromatography and it's 100% correct. Check this http://www.scribd.com/doc/8071912/Caffeine-Extraction

yeah i wrote chromatography method

 

[ThatReallyReallyWeirdDude]

That was the only question I invented answers in haha

Oh
Solid was Ammonium Carbonate.

 

[shalala]

Hahahha It is Ammonium Carbonate, as it releases amonia when heated with NaOH. and they said it's carbonate.

what happens when silver nitrate reacts with the aqueous potassium??

yeah i wrote chromatography method

 

[Omar Hosny]

Guys guys remember that there is something called Error Carried Forward, i think the reaction was Exo or PPT or Displacement...For easy dissolving I wrote more heat supplied + dissolve by a glass rod

 

[jasmineRocks]

srsly?!!....bt e ere supposed to dra a straight line...and one of them jst didnt fit in!! :S

I think we had to multiply the points by 10 so the first point would be 4 and so on by this way you will get a straight fixed line and i hope we all get it correct inshallah and good luck

 

[shalala]

I think we had to multiply the points by 10 so the first point would be 4 and so on by this way you will get a straight fixed line and i hope we all get it correct inshallah and good luck

what happens when silver nitrate reacts with the aqueous potassium??
and why were the height same for the soliudd?

 

[zaid1q]

i wrote temperature rise will be higher because copper is an insulator ://// i gain 1 mark out of 2 right?

 

[Patum]

I already solved a past paper about it, they said exothermic so shut up please.

it's exothermic so dw..

 

[Nawaf Dandachi]

Oh
Solid was Ammonium Carbonate.

No I knew it was ammonium carbonate, I meant for the boiling Iron II sulphate question

 

[Nawaf Dandachi]

it's exothermic so dw..

It's Desplacment, How did you know it's EXO?

 

[Nawaf Dandachi]

i wrote temperature rise will be higher because copper is an insulator ://// i gain 1 mark out of 2 right?

Yeah.

 

[Nawaf Dandachi]

what happens when silver nitrate reacts with the aqueous potassium??
and why were the height same for the soliudd?

Dear, Potasium IODIDE + SILVER NITRATE, isn't that a test of??? It shows yellow precipitate

 

[Patum]

what happens when silver nitrate reacts with the aqueous potassium??
and why were the height same for the soliudd?

the height were all the same because 5 cm^3 used up whole of 3cm^3 of lead nitrate which gave 24cm height. therefore any amount bigger than 5 cm^3 reacts with 3cm^3 of lead nitrate you won't get anything more besides 24 cm. basically all the lead nitrate gets used up when you have the other substances which is 5cm^3 or above reacting with it. so maximum it goes is to 24 cm

 

[L-Girl]

It's Desplacment, How did you know it's EXO?

i believe Exothermic is correct. All displacement reactions are exothermic!

 

[Nawaf Dandachi]

How to speed up disolving in number 3, you don't say heat, as they told you the water is hot.

Say " Stiring with glass rod"

 

[ThatReallyReallyWeirdDude]

No I knew it was ammonium carbonate, I meant for the boiling Iron II sulphate question

Oh
For the boiling I wrote that it's gonna form a saturated solution and with further boiling crystals of hydrated iron sulphate would form.

 

[Nawaf Dandachi]

i believe Exothermic is correct. All displacement reactions are exothermic!

so, It's desplacment!

 

[Patum]

It's Desplacment, How did you know it's EXO?

It's exo because the TEMPERATURES in the thermometers increased. This is a sign that it's an exothermic reaction ( Exothermic reactions release heat)

 

[ThatReallyReallyWeirdDude]

It's exo because the TEMPERATURES in the thermometers increased. This is a sign that it's an exothermic reaction ( Exothermic reactions release heat)

They didn't give thermometer temperatures. Just cm3 of potassium chloride and mm of precipitate.

 

[Nawaf Dandachi]

Did they say so?