Paper 5 Tips !! :)

[MaxStudentALevel]

Wait i might be wrong but for solubility dont you discard the residue (Not the saturated solution). You filter of the saturated solution and (Discard the residue). Then weigh the saturated solution. You then heat the saturated solution and you'll have a residue left, then you pour propanone on that (and not what you had initially). You can then warm this lightly via a water bath and carry this on till a constant mass attained. Then you just have to subtract this mass from the initial saturated solution mass and use the formula.
Atleast this is what i followed all this time.

Yes, that's the method I'm familiar with also. That's what makes sense.
---> I haven't thought this through but you could also calculate mass of dissolved by the excess as all you have to do is subtract?

 

[MaxStudentALevel]

How to get the green part ?

Now I'm doing this from memory, I'm in bed and I have an exam tommorow but I couldn't resist answering:
-I'm pretty sure it's 0.02/50 (as 25cm3 is the original solution volume) the x2 comes from
2 COOH groups in succinc acid.

Understand??

 

[seneria]

reply to my question too please. max student a level

 

[MaxStudentALevel]

reply to my question too please. max student a level

I'm actually going to bed right now, I can't get up and go check the paper as I don't have that particular question in mind.
I'll try to answer Tommorow after my exam if your question is still unresolved by then!

 

[seneria]

okay no problem...

 

[Silent Hunter]

Now I'm doing this from memory, I'm in bed and I have an exam tommorow but I couldn't resist answering:
-I'm pretty sure it's 0.02/50 (as 25cm3 is the original solution volume) the x2 comes from
2 COOH groups in succinc acid.

Understand??

thank you..... (sorry for disturbing)

thanks again

 

[xhizors]

Wait i might be wrong but for solubility dont you discard the residue (Not the saturated solution). You filter of the saturated solution and (Discard the residue). Then weigh the saturated solution. You then heat the saturated solution and you'll have a residue left, then you pour propanone on that (and not what you had initially). You can then warm this lightly via a water bath and carry this on till a constant mass attained. Then you just have to subtract this mass from the initial saturated solution mass and use the formula.
Atleast this is what i followed all this time.

you can use it either way u'r doing actually same except
" Then you just have to subtract this mass from the initial saturated solution mass"
by this u'll get the mass of water which is dissolved
the first way is another approach as u don't have to get the crystals by evaporating all of the water dissolved
by your method the mass of residue from the saturated solution is the exact mass which is dissolved
the method stated above tells us how much mass have been used up from the used up mass! by substracting the residue of undissolved mass and the mass used

hope this helps!

 

[xhizors]

xhizors

JazakAllah-o-Khair You have done a GREAT job MashAllah
Don't we have to place the plastic cup in beaker in enthalpy change questions?

yup u can in a little big beaker to avoid heat loss(plastic cup is also a good heat insulator)

 

[xhizors]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_52.pdf
the graph in a) ii) ? looks easy but the ms isn't clear :/

?? whats the prob?

 

[xhizors]

Can you guys also suggest a sensible diagram for NOV10/53 q1
What sort of internal separation device will be used here to separate H2O2 and the catalyst??

I too was puzzeled in this, i tried two workOuts
a) placed a solid cube of Mg..
b) used a flask with an inlet (throw in MG.. with connecting tubes connected to supply)
what u thought

Edit:
googling helps
http://www.techknow.org.uk/wiki/index.php?title=File:Catalase.jpg

 

[Nibz]

Good work, xhizors. I hope and pray you get your World Distinciton. =)

Thread made sticky till 10th May.

 

[xhizors]

Good work, xhizors. I hope and pray you get your World Distinciton. =)

Thread made sticky till 10th May.

JazakAllah

 

[xhizors]

What u guys did for apparatus setup in n12/51 ?
i consulted my friend and found out that H2O evaporated can be condensed and H2 wont so i placed ice bath and gas syringe to the same connecting tube !

 

[Kinjal]

Hi everyone..
I needed help with this ppr..Qn 2 the graph..either how the graph looks or only the coordinates will also be very helpful..
Pleasee help ASAP!
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s09_qp_5.pdf

 

[xhizors]

Hi everyone..
I needed help with this ppr..Qn 2 the graph..either how the graph looks or only the coordinates will also be very helpful..
Pleasee help ASAP!
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s09_qp_5.pdf

Their would be to lines one at higher temperatures (solubility temperature) and the other at lower temperature (crystals appearing)
on x-axis Temperatures and on Y-axis Solubility
u extend both of these lines and the point of intersection is their transition temperature!

 

[AmoooMMM]

i have a question if anyone culd pleaaaaase help me out
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_53.pdf
question2 b part iii , iv and v pleaase

 

[xhizors]

Another and more known Method to calculate solubility of a compound in water(lol try it in your own kitchen)

Solubility refers to highest amount of a dissolvable substance, also known as a solute, that can actually be dissolved in a given dissolving substance, also known as a solvent. In terms of science experiments, you can determine the solubility of given household items, such as table salt, Epsom salt and sugar, by testing it yourself at home. All you need is solutes, water and a scale to begin dissolving and measuring these ingredients.

Instructions

1. Method One
   
   
   • 1​
     Add 100 ml of water to a clean beaker. The water should be distilled for best results. If you do not have a beaker, you can use a clean glass jar.
   • 2​
     Use an electric kitchen scale to measure out 50 grams of table salt, 50 grams of Epsom salt, and 250 grams of sugar. The table salt should be non-iodized.
   • 3​
     Add a small amount of the salt to the water and stir it with a clean, plastic spoon. Stir the mixture continuously until the salt is dissolved. Continue to add small amounts of the salt to the water and stir it until it dissolves.
   • 4​
     Measure the remaining salt once it will no longer dissolve. Record the results.
   • 5​
     Repeat the previous two steps for the Epsom salt and the sugar in separate beakers of 100 ml distilled water each.
   • 6​
     Calculate the solubility of each solution by subtracting the ingredient you did not mix into the water from the sum of the water volume and the amount of the ingredient you added.
   • 7​
     Save all three solutions for the second method.
   Method Two
   
   
   • 8​
     Use a piece of tape and a marker to label the bottom of three small, shallow plates. The labels should read table salt, Epsom salt, and sugar and the plates should be ovenproof. Weigh the empty plates on your electric kitchen scale and record the results. Do this with all three plates even if they are the same style. There may be a slight variance in weights.
   • 9​
     Pour 15 ml of each solution from the first method into the plate with the corresponding label. Weigh each plate again and record the new weight.
   • 10​
     Place all three saucers in a preheated oven set at 250 degrees Fahrenheit. Leave them in there until the water evaporates, which will vary based on your altitude and the air conditions that day.
   • 11​
     Use oven mitts to remove the plates from the oven. Be careful since they will be very hot. Weigh the plates again on the kitchen scale after all the water has evaporated. Record your results.
   • 12​
     Calculate the mass of the evaporated water by subtracting the mass of solution after evaporation from the mass before evaporation.

Tips & Warnings

• ​
  You should repeat both methods at least three times for each solution to ensure you have accurate results.
  Source:http://www.ehow.com/how_5711733_measure-solubility-science-project.html

​

 

[Gémeaux]

xhizors
Aoa,
I need help with this one, please.
9701/51/M/J/12 Question 1 a(ii)

Are these co-ordinates correct? Plus, the question states to *label* the point representing the saturated solution of CuSo4, how do we do that? (m.s. doesn't mention them :/)

 

[Student12]

Their would be to lines one at higher temperatures (solubility temperature) and the other at lower temperature (crystals appearing)
on x-axis Temperatures and on Y-axis Solubility
u extend both of these lines and the point of intersection is their transition temperature!

What column headings are we going to take to get the solubility and how to calculate?

 

[PhyZac]

To find the solubility of any solid dissolved in any solution
Take 250 cm3 conical flask pour 50 cm3 of water
weigh a sample of solid and add it into water and stirr it until no more solid dissolves
then leave it for sometime to cool down to give crystals
filter the solution transfer the residue and discard the saturated solution
wash the residue with distilled water thoroughly and discard water then add propanone to absorb any water droplet left
warm a little or place the container under oven or sun (not bunsen burner else it will decompse solid) to evaporate any propanone left
now weigh the residue
repeat until constant mass is acheived
substract mass if residue with the initial mass so u'll get mass of solid dissolved to make a saturated solution,
now to find solubility use ( mass of solid use x 100)/mass of water

I dint get this experiment sorry.

like what to repeat??