Chemistry: Post your doubts here!

[donewithtime80]

Anyone?

It's CNO- .... cause CO(NH2)2 (minus) NH4+ = CNO-

 

[donewithtime80]

http://studyguide.pk/Past Papers/CIE/International A And AS Level/9701 - Chemistry/9701_w06_qp_1.pdf

q: 1, 4 and 9

 

[The Sarcastic Retard]

http://studyguide.pk/Past Papers/CIE/International A And AS Level/9701 - Chemistry/9701_w06_qp_1.pdf

q: 1, 4 and 9

1) CaSO4 + 2KOH ----> Kn2SO4 + Ca(OH)2
n of KOH = 2.5 * 10^-4mol
1 : 2 ratio
so n of CaSO4 = 0.5 * n of KOH = 1.25 * 10^-4
c = n/v
c = A

4)


9)

 

[The Sarcastic Retard]

View attachment 57496

It was solved yesterday only... check few pages back

 

[awesomaholic101]

Yes it is. Thank you!

you're welcome

 

[awesomaholic101]

View attachment 57496

lol just multiply the abundance with the Mr ... and choose the highest value

 

[awesomaholic101]

So prepared?

uhh ... many concepts i am making mistakes ... planning to go through the textbook if that's even possible now

 

[The Sarcastic Retard]

uhh ... many concepts i am making mistakes ... planning to go through the textbook if that's even possible now

Go through the once in which u make most mistakes.

 

[awesomaholic101]

Go through the once in which u make most mistakes.

yeah


23rd question please

 

[donewithtime80]

In a car engine, non-metallic element X forms a pollutant oxide Y. Further oxidation of Y to Z occurs spontaneously in the atmosphere. In this further oxidation, 1mol of Y reacts with 0.5mol of gaseous oxygen.

is it oxides of carbon or nitrogen?

 

[donewithtime80]

When a firework is lit, a fuel and an oxidising agent react together.
In one such firework, magnesium is the fuel and barium nitrate is the oxidising agent.
Which solids are produced when the firework is lit?

1 BaO
2 MgO
3 Mg(NO3)2

BaO and MgO are produced.... but isn't it suposed to be MgNo3)2 too?

 

[ahmed butt]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s14_qp_11.pdf
http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s14_ms_11.pdf
Q29?

 

[ahmed butt]

When a firework is lit, a fuel and an oxidising agent react together.
In one such firework, magnesium is the fuel and barium nitrate is the oxidising agent.
Which solids are produced when the firework is lit?

1 BaO
2 MgO
3 Mg(NO3)2

BaO and MgO are produced.... but isn't it suposed to be MgNo3)2 too?

it will produced then it will convert to MgO ,O2,NO2 due to heat applied

 

[Metanoia]

Could you please show the equations as I'm slightly confused how you know there are two Fe3+ ions for each Fe2(SO4)3

Fe2(SO4)3 (aq) --> 2 Fe3+ + 3 SO42-

 

[Sinzzzz]

heyy!
can someone explain this please
Alkane X has molecular formula C4H10. X reacts with Cl 2(g) in the presence of sunlight to produce only two different monochloroalkanes, C4H9Cl. Both of these monochloroalkanes produce the same alkene Y, and no other organic products, when they are treated with hot ethanolic KOH. What is produced when Y is treated with hot concentrated acidified KMnO4?
A CO2 and CH3CH2CO2H
B CO2 and CH3COCH3
C HCO2H and CH3COCH3
D CH3CO2H only
The answer is B. But i thought it would be A.

 

[donewithtime80]

why isn't it B and Y D?

 

[donewithtime80]

26 Use of the Data Booklet is relevant to this question.
2.30 g of ethanol were mixed with aqueous acidified potassium dichromate(VI).
The desired product was collected by immediate distillation under gentle warming. The yield of product was 70.0%.
What mass of product was collected?

A 1.54g
B 1.61g
C 2.10g
D 3.14g

 

[The Sarcastic Retard]

yeah

View attachment 57497
23rd question please

The answer is C because, the minimum number of carbon required for having isomers is 4. So C is the only option where when u crack alkane u will get 4 carbon atoms in each hydrocarbon.
A and B cannot have isomers. C-C and C-C-C
D is straight out.

 

[The Sarcastic Retard]

In a car engine, non-metallic element X forms a pollutant oxide Y. Further oxidation of Y to Z occurs spontaneously in the atmosphere. In this further oxidation, 1mol of Y reacts with 0.5mol of gaseous oxygen.

is it oxides of carbon or nitrogen?

Nitrogen. Carbon monoxide dont oxidizes spontaneously.

 

[awesomaholic101]

The answer is C because, the minimum number of carbon required for having isomers is 4. So C is the only option where when u crack alkane u will get 4 carbon atoms in each hydrocarbon.
A and B cannot have isomers. C-C and C-C-C
D is straight out.

ohh right ok thanx