Chemistry paper 31 (NEW)

[xIshtar]

name a reaction that includes light ? i wrote photosynthesis is that right
name a device that convert chemical energy into electrical ?? i wrote motor but i thought it was a battery

I wrote photosynthesis and a cell

 

[nightwalker221]

I think its a B
But it really depends on the threshold.

 

[moonlight22]

Thanks !

 

[WayneRooney10]

Yeh, the moles was hard.
By the way, when does the result of IGCSE come.

11 August

 

[nightwalker221]

Does anyone know how the cambridge folk talke out the percentage of the chemistry Papers 1, 3, and 6.
If you know just tell the method.
Thanks

 

[AhmedNES]

if ur average percentage is above 84% its an A*

 

[AhmedNES]

mainly above 80% ur most likely to get an A*

 

[nightwalker221]

If i get 75%
is that an A.
thanks for telling

 

[farhan143]

dude isnt 90-100% supposed to be A*??

 

[AStarHunter]

guyz, it differs from year to year depending on the grade boundaries !

 

[WayneRooney10]

You can get A at 60%. A* at 70%.

 

[Ramosk95]

guys i found this post in studentsforum.biz
Many people have been asking about the new grade policy. In fact this is the most frequent qst that i'm coming across. I replied many pm's too but here is an example for those who still have confusions after reading my earlier topic on the new grade policy.

Assume there are 2 papers of subject X. P1 has 40 marks. And p2 has 60 marks. If in July CIE sets the minimum number of marks required for an A in p1 as 32/40 and for a B as 29/40. Likewise it sets A at 52/60 in P2 and B as 48/60 in P2. So, you need a minimum of this to achieve the required grade in each paper. Now, CIE will total your number of marks. One thing is for sure the minimum required to get A* will be set as many marks above the sum of the Grade A minimum as the grade B is below it. In this example:

for B: 29 + 48 = 77/100

FOR "A" 32 + 52 = 84/100.

Now CIE will subtract the minimum for a B from A.

Hence, 84-77 = 7 marks.

These will be added to the sum of A grade marks i.e. 84 + 7 = 91 marks. Therefore, 91/100 will be the minimum for an A*.

So, you can see it is not necessary to get a minimum in each paper. If you got say 31/40 in P1 it'll be given grade B according to our assumptions above. And if you got 60/60 in P2 you'll get an A in p2. But the total will be 31 + 60 = 91 marks. Hence, you've achieved the minimum for A* .

The minimum for A* that is 91/100 in our example will be mapped onto a percentage uniform mark of 90%.

The minimum for A in our example 84 will be mapped onto a percentage uniform mark of 80% .

Thats how it will work

 

[nightwalker221]

What do you guys think about the threshhold of paper 3 this time?

 

[nightwalker221]

Hi,
if i get:
42/60 in P6
35/40 in P1
60/100 in P3
What will be my percentage?
Thanks

 

[WayneRooney10]

Hi,
if i get:
42/60 in P6
35/40 in P1
60/100 in P3
What will be my percentage?
Thanks

U mean 60/80?
hmm. U might get an A*

 

[nightwalker221]

Well,
i calculated in paper 3.
My butylethanoate one was wrong, the moles was wrong and one of the polymers i made was wrong.
So you can subtract (if threshold for A is 60) 20-3-3-3-2-2-2-2-2=1 so the other 2's are marks cut for some small mistakes. Rest of the paper was good.

 

[DV3looy]

the exam wasn't that hard nor easy the exam was OK

some question were complicated, but i think that i will get from B+ and above

the exam was good :good: :good: :good: :good: :good: :good: :good: :good:

 

[NOOB12345]

Agreed, I find the chemistry 31 pretty damn hard, and I not even bad at chemistry (usaully A to A star). The format and style is totally different, it's more biology and physics like. Those who found it easy might not even realized the number of mistakes they might have made, or maybe they did a different variation which is easier. Of course it also depends on what you are aiming for and your own standards. What do think the boundary for A will be this year? 40/80 or 50/80?

I find the science exams this year generally harder than previous years, Physics and Biology Paper 3s wasn't that difficult to me, but hell they sure are long. Normally I can finish paper 3s 10 minute before, but this time I barely managed to finish on time.

By the way remember the question about Selenium (or was it some other metal)? What type of reactant is it acting as? I wrote it's acting like a Base, as it accepts a proton as hydrogen ion. (Note: I am not talking about the redox/reduction/oxidation question, sry if I mixed up). lol I can't even remember all the questions :OOOOO

 

[DowntownCrew]

I see you guys are talking about percentages so I wanted to ask a question ; Can someone put percentages for grades A*-D , just most probable or average percentages according to last years , I would like to know it.

 

[nightwalker221]

The selenium one was that it is acting as a reducing agent because it removes the Oxygen from the what ever the reaction was. I forgot it.