Biology; Chemistry; Physics: Post your doubts here!

[Dawarkazi]

please answer this also!

 

[AhsanAfzal]

the change is due to difference on rate of diffusion. so the gas must have same molecular mass as N2. 28 is Mr of N2 so is of CO. therefore CO is answer. same Mr same diffusion rate, no change.

got it

which gases move through porous pot? Suchal Riaz Saad Mughal

 

[Dawarkazi]

please answer this also!

which gases move through porous pot? Suchal Riaz Saad Mughal

B is the answer

 

[simranlalchand]

The acid G contains two carboxylic acid groups and has the formula
HO2CCxHyCO2H
where x and y are whole numbers.
Deduce the values of x and y in the formula. given the molecular mass of G is 132g

 

[sourov97]

please answer this also!

KMnO4 is a oxidising agent, but Fe3+ is already in its highest oxidation state and cannot be further oxidised to Fe4+

 

[sourov97]

The acid G contains two carboxylic acid groups and has the formula
HO2CCxHyCO2H
where x and y are whole numbers.
Deduce the values of x and y in the formula. given the molecular mass of G is 132g

which year?

 

[Saad Mughal]

The acid G contains two carboxylic acid groups and has the formula
HO2CCxHyCO2H
where x and y are whole numbers.
Deduce the values of x and y in the formula. given the molecular mass of G is 132g

2 Carboxylic groups have mass (2*45) = 90.
Therefore mass of CxHy = 132 - 90 = 42
Hence,
12x + y = 42
Apply trial and error,
when x = 3,
36 + y = 42
y = 6.
x cannot be greater than 4.
At x = 2, y = 18.
At x = 1, y = 30.
Both of which are not possible.
Hence, x = 3 , y = 6.

 

[AhsanAfzal]

can carbon dioxide go through cotton wool?

 

[Saad Mughal]

can carbon dioxide go through cotton wool?

Yes.

 

[Suchal Riaz]

Saad Mughal
help needed man. Potassium Manganate is a base? if yes what is it's formula and it's equation with reaction with an acid. and color change. everything we need to know about it.

 

[AhsanAfzal]

is dehydration of alcohol in the syllabus

 

[Khadija_1234]

the water level didn't change...this means that if there was any change of gases between the porous pot and the inverted beaker, the molecular mass of that gas should be equal to that of CO (12 + 16 = 28).
(d) nitrogen (gas) is the answer. (14 + 14 = 28)

Okay thanks
So if the water level had raised, what would that have indicated?

 

[Suchal Riaz]

AhsanAfzal Khadija_1234 please:
Potassium Manganate is a base? if yes what is it's formula and it's equation with reaction with an acid. and color change. everything we need to know about it.

 

[Saad Mughal]

Saad Mughal
help needed man. Potassium Manganate is a base? if yes what is it's formula and it's equation with reaction with an acid. and color change. everything we need to know about it.

It is a metal - metal - oxide. KMnO4 is it's formula. Manganate has valency +7.
It is an oxidizing agent. It is a salt.

 

[AhsanAfzal]

AhsanAfzal Khadija_1234 please:
Potassium Manganate is a base? if yes what is it's formula and it's equation with reaction with an acid. and color change. everything we need to know about it.

acidified aqueous Potassium manganate is oxidising agent and changes from purple to colourless after reducing itself

 

[simranlalchand]

which year?

w12 qp 42

 

[Saad Mughal]

acidified aqueous Potassium manganate is oxidising agent and changes from purple to colourless after reducing itself

Acidified Potassium Manganate (VII) is an even stronger oxidizing agent. Potassium Manganate (VII) simply is an oxidizing agent.

 

[abdullahcheema03]

http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_s12_qp_42.pdf
Q4 plz help

 

[Kamihus]

http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_w12_qp_41.pdf
Q#9e

 

[Suchal Riaz]

Acidified Potassium Manganate (VII) is an even stronger oxidizing agent. Potassium Manganate (VII) simply is an oxidizing agent.

man i have seen it in titration?