Chemistry Paper 61

[ThatReallyReallyWeirdDude]

For that experiment I wrote:
Place a nail in each of 4 test tubes with 30cm3 of water.
In three of the test tubes place 10 cm3 of corrosion inhibitor (so R/S/T are in a seperate test tube and one is left empty)
Measure the mass of each test tube + it's contents
Then every 12* hours measure the new mass + rust which has formed, and use this + original mass to find increase in mass
a) If R/S/T actually inhibit rusting then there rate of increase of mass (due to rust formation) will be less than that of the tube without any retardant (the control one)
b) The best inhibitor will have the smallest rate of increase of mass

[I wrote them both cause it asked to prove that they inhibit rust AND to show how to find out which one is best]
EDIT: I wrote 12 hours (half a day) not six.

 

[EpicLol]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w10_ms_62.pdf

I checked it and I think I will get like 4-5 marks out of 7 because I mentioned to use 1 nail in each testtube and I added another test tube with no like rusting stoping thing as the control hope that wont annoy the examiners... XD

 

[ZainH]

that answer wont make sense
they are providing u hot water
you increased surface area with crushing
only thing left is to add more water(in excess) or stir the solution

It's not that hard to understand how HEATING would speed up rate of reaction.
Sure they provided you with hot water, but was a temperature specified ... no? Over time the solution would cool, causing a decrease in the rate.
IF we apply heat constantly throughout the experiment, the temperature will not FALL , it will only RISE, which will INCREASE the rate of reaction.
Im sorry I can't explain this in more simpler terms.. if you still think the answer doesn't make sense , eh it's fine. No one knows what they will accept, so lets just await our grades in august!

 

[Z.A.M]

Im not saying stirring is wrong, I'm just saying heating isn't wrong. It could be accepted.

Yeah it cud be

 

[ThatReallyReallyWeirdDude]

Im not saying stirring is wrong, I'm just saying heating isn't wrong. It could be accepted.

Actually
I think heating is wrong
They SPECIFICALLY mentioned hot water. It's a trick on their part.
But that's a matter of opinion. For all you know the water was at its boiling point and further heating would just evaporate it.

 

[ZainH]

Actually
I think heating is wrong
They SPECIFICALLY mentioned hot water. It's a trick on their part.
But that's a matter of opinion. For all you know the water was at its boiling point and further heating would just evaporate it.

Either that, or it wasn't even near 70 degrees, and further heating would increase the rate.. Who knows!
And honestly, it's one mark so who cares . Hopefully they'll accept both x)

(Check your inbox btw >.>)

 

[Z.A.M]

what is the total mark for this paper 6? I think its like 65? but Im not sure....

It's 40

 

[EpicLol]

what about the crystalisation question? I said heat it and then add more of the solution so that more of it dissolves in the water (until it becomes saturated) and after doing this then you let it cool down slowly so that crystals form....how many do u think I will get out of 3 marks?

 

[Z.A.M]

Actually
I think heating is wrong
They SPECIFICALLY mentioned hot water. It's a trick on their part.
But that's a matter of opinion. For all you know the water was at its boiling point and further heating would just evaporate it.

Oki so dudes it's just freaking 1 mark?
Anyways any1 here freaked for Physics p3 cuz I totally am

 

[Hamzeh S]

Guys i want you to grade me please im really worried first exam i worry about i get the apartus and curves right .. and last question first page i wrote cryastallization and to make solvent more solube how know if reaction finished i wrote residue of iron powder and the second point is wrong nvm about it anw i lost a mark about what kind of reaction and a mark on what happens if you mix iodide and silver nitrate qualtative analysis nailed it so did the question about the filter diagram the readings i had no mistakes but last question i wrote to put each iron nail in seperate test tube add water (rusting conditions ) add the inhabitors and compare the results see which one rust and which ones rust faster please how much you think i can get im really worried sorry for troubeling you and reading all this

 

[Z.A.M]

what about the crystalisation question? I said heat it and then add more of the solution so that more of it dissolves in the water (until it becomes saturated) and after doing this then you let it cool down slowly so that crystals form....how many do u think I will get out of 3 marks?

That's right wrote that hope we get 3

 

[EpicLol]

It's 40

That cant be right....I roughly counted at the end and it came like upto 60-70 marks....it cannot be 40....if it is then I did horrible coz I think I lost like about 8-10 marks....

 

[Z.A.M]

That cant be right....I roughly counted at the end and it came like upto 60-70 marks....it cannot be 40....if it is then I did horrible coz I think I lost like about 8-10 marks....

I dunno dude it's always outta 40 for all otha papers iznt it

 

[Nawaf Dandachi]

Guys, Let's forget about the exam and let's focus on the exam tomorrow Business AS paper 2.
Good Luck.
"Never look back"

 

[EpicLol]

for paper 1 its 40 thats for sure...apaper 3 and 6 I think its more...I hope its more....I really do....

 

[Z.A.M]

Wat r u guys doin for physics

 

[EpicLol]

Does anyone have a list of grade thresholds of chemistry for like 5-6 previous exams so taht I roughly know what an A grade would need? Thx

 

[Z.A.M]

I know the thread says chemistry p61 but seriously wat r u guyz doin for physics p3 it's major me freaking out lyk hell

 

[EpicLol]

Wat r u guys doin for physics

Im not doin a lot of revision for physics coz I think Im better at it than I am in chemistry....any revision sheets, formula sheets and other key points etc would be greatly appreciated thx

 

[ZainH]

Guys, Let's forget about the exam and let's focus on the exam tomorrow Business AS paper 2.
Good Luck.
"Never look back"

YOU can focus on business, because I don't take it x)
I'll focus on physics for friday :S