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Paper 5 Tips !! :)

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and brother Ashique , the diagram u posted above.. it doesnt show the excess H2 is being taken care of... is that what the gas syringe is for?
 
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s11 :51 2c could some please picture or scan the graph for me ?! please thank u
 
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and brother Ashique , the diagram u posted above.. it doesnt show the excess H2 is being taken care of... is that what the gas syringe is for?

It does. You see the "excess gas burning" at the end of the tube? That's the excess H2 being burnt. Check the ms, it also says the same thing! :)
The gas syringe is there because, according to the question, we need a volume of gas to react with the oxide of lead. To collect this very precise volume, the syringe has to be connected to a test tube (or conical flask) in which the reaction between a metal and an acid gave off the H2.
 
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Isn't that wrong? The question asks you to draw a line of best fit. You drew a curve. :unsure:
Yeah.. but look at what the mark scheme says:)
And why is my diagram wrong? Can you please explain what excess gas burnt means?
Thanks.
 
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Friends can you please help me how to calculate solubility and molality. what are the formula to calculate these?
May you all get A's and A*.
 
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Friends can you please help me how to calculate solubility and molality. what are the formula to calculate these?
May you all get A's and A*.
solubility=( mass of solid/ mass of water ) x 100
molality= no of moles of solute dissolved in 1kg of water
 
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Yeah.. but look at what the mark scheme says:)
And why is my diagram wrong? Can you please explain what excess gas burnt means?
Thanks.


Right! Didn't notice the co-ordinates! :p

The burning of the excess gas was covered in IGCSE (or O level if you're in the South East). The the heating of the apparatus provides enough activation energy for the excess gas to burn (as H2 could be hazardous since it is extremely flammable)
 
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Alright, underline your kewords as you read the question.. tell me what you're gonna label your columns..i'll guide you inshAllah.

i labelled my coloums as

mass of water/gm (C-B)
mass of solid/gm (E-D)
and i calculated solubilty by diving (E-D)/(C-B) i.e F/E.
Did i did correct? Thank you.
 
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