Chemistry P2 :)

[likosp]

What was the answer of the MCQ in which we had to identify the reason why aluminium does not react with copper at room temperature or something like that. is it because aluminium is inert?

THats absolutely correct if youve read about the properties of aluminium it is known that aluminium has an inert oxide coat over it and heat has to be supplied to it for the oxide layer to get off the aluminium ,,,, the option D wasalso tempting but it was incorrect as aluminium is above zinc in react. series so it should very easily react with zinc without any heat thats why it wasnt correct

 

[Chicharito]

What were the answers to the first question of paper 2?

 

[likosp]

What were the answers to the first question of paper 2?

i dont remember the question the one that was a white solid and alkaline in water was sodium hydroxide.

 

[Chicharito]

Ok. And what was the answer to the fractionating column mcq. The one in which we had to Identify some uses. I don't remember the question correctly :/

 

[likosp]

That was lubricating oil its used for polishes and waxes..

 

[Chicharito]

Yes Thank God!

 

[likosp]

Anything else ????

 

[donor]

What was the answer to the mcq question which asked what is the ion present in the solution if a reagent was added before a precipitate was seen

 

[Chicharito]

Do u remember the mass of Mg in the graph question in Section B?

 

[likosp]

tha ion was calcium as it is insoluble so no matter how fast the NaOH was added the ppt wudnt dissolve...
@chicharito no remind me of the question...

 

[Chicharito]

@likosp I don't remember it properly but the question asked us to find the mass of Mg by using info from the graph

 

[likosp]

do you remember your answer??

 

[ibadsiddiqi]

mass of magnesium was 0.06 grams

 

[Chicharito]

Yes. I was getting 0.06 grams aswell

 

[likosp]

mass of magnesium was 0.06 grams

the equation was 2Mg+HCl = MgCL2 + H2
we were give a volume of hydrogen = 60cm3
moles of hyd. = 60/24000 = 0.0025
ratio= 1:2
so moles of Mg were 0.005
mass= 0.005 * 24(mass number of Mg)
=0.12
Pls tell me what iv done diff. frm you bcause i still dnt remeber my answer in the paper or the volume of hydroen very clearly....

 

[ibadsiddiqi]

dude the ration was 1:1

 

[ibadsiddiqi]

look at you equation! You have two moles of magnesium, 1mole of hydrogen and 1 mole of chlorine on the left hand side while on the right hand side you have 1 mole of magnesium, 2 moles of chlorine and 2 moles of hydrogen. The correct equation is Mg+2HCl---->MgCl2 + H2

 

[likosp]

ahahaah that mmeans i probably did right thanks for that if uv got anyore queries do ask....

 

[Usman17]

it was D that the reaction required temp to start

DUDE it was due to the inert coating of aluminium!!

 

[Chicharito]

What was the equation of Mg with Flourine? And what was the charge?