Biology; Chemistry; Physics: Post your doubts here!

[Mahnoorfatima]

And what is the color change at end point?
It says Colorless to pink. :/ Why is Iron Sulfate colorless?

WHAAAAT! How can FeSO4 be colourless. It has to be green, no?

 

[Dark Destination]

Dude when a carboxylic acid reacts with a metal like Na metal the product is salt and H2 gas right? So as the acid is a weak one, thus 1/2 H2 has to be produced EVERYTIME?

H2 is just produced. There is no half half

Who told you its half? o.o

 

[Dark Destination]

WHAAAAT! How can FeSO4 be colourless. It has to be green, no?

But how will green turn to PINK, when KMnO4 is added in excess?
Won't it turn to Iron (III) Sulfate, which itself has a color.

 

[Mahnoorfatima]

H2 is just produced. There is no half half

Who told you its half? o.o

Idk! Its in the reactions.. My teacher give me.. Atleast the reaction with Na metal produces 1/2 H2. When you balance it.

 

[Mahnoorfatima]

But how will green turn to PINK, when KMnO4 is added in excess?
Won't it turn to Iron (III) Sulfate, which itself has a color.

Gimme the question?

 

[Awesome12]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s10_qp_42.pdf
Question number 6, the graph one.

The graph is steeper AND the volume at the end has doubled.
So shouldn't the answer have double the volume AND double the concentration as it is steeper too? :| Confused. Halhp.

P.s; how's everyones preparation going?

No. If we double the volume, the rate of reaction will be halved and it will be slower. In this case, we will stick to the same vol. Doubling the conc. will increase both the rate of reaction and amount of products formed.

 

[Dark Destination]

Idk! Its in the reactions.. My teacher give me.. Atleast the reaction with Na metal produces 1/2 H2. When you balance it.

It's a simple Acid + Metal reaction.
You just have to balance it, and do the calculations.

There is no law in chemistry that it will be always HALF.
And even that HALF, is about the MOLES ratio. It must be half of one of the reactants moles.

 

[Awesome12]

But how will green turn to PINK, when KMnO4 is added in excess?
Won't it turn to Iron (III) Sulfate, which itself has a color.

KMnO4 is itself purple. So if we add more of it, the solution will most certainly turn purple

 

[Dark Destination]

KMnO4 is itself purple. So if we add more of it, the solution will most certainly turn purple

But isn't IRON (III) Sulfate there?
Doesn't it have a color too?

And why do we add Sulfuric acid to Iron (II) Sulfate before this titration? :/

 

[Mahnoorfatima]

KMnO4 is itself purple. So if we add more of it, the solution will most certainly turn purple

Could you please give me the question? :/

 

[Dark Destination]

Could you please give me the question? :/

It's not one question. It's everywhere. In every Redox titration question..

 

[Mahnoorfatima]

Ok Off to bed. Good Luck everyone. Inshaa ALlah the paper will be easy. May Allah help us tomorrow! Ameeeen!

 

[exploded diper]

so if we increase concentration , temperature, catalyst, the graph is steeper -- Yes
and if we increase volume the volume of gas is more so graph is higher.. -- Yes

if we increase concentration does the volume of gas also increases so graph is both steeper and higher ? -- Steeper only
and if we decrease volume and increase concentration the graph is steeper but at the same height ....-- Less height
am i correct????

i think graph is also higher ....
and since the moles will remain unchanged so wouldnt the height remain same???

 

[exploded diper]

i think graph is also higher ....
and since the moles will remain unchanged so wouldnt the height remain same???

Awesome12 can u ans this question........i am a bit confused bout this stuff........

 

[Awesome12]

Awesome12 can u ans this question........i am a bit confused bout this stuff........

Which question. I already answered 2 different people today regarding this

 

[Laibaaa]

Can I skip the Fats wala macromolecule? its hard

 

[princess Anu]

Please explain this unique question Q8(K)
http://papers.xtremepapers.com/CIE/...al O Level/Chemistry (5070)/5070_w08_qp_4.pdf

 

[Dark Destination]

Can I skip the Fats wala macromolecule? its hard

Of course. That stuff doesn't come in ATP.

 

[Dark Destination]

Please explain this unique question Q8(K)
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_w08_qp_4.pdf

What does the marking scheme say?

 

[funky brat]

Why do I miss the alerts? :/