Chemistry: Post your doubts here!

[ahmed butt]

Anyone?

Just memorise its always CNO- its always repeating

 

[The Sarcastic Retard]

Just memorise its always CNO- its always repeating

I want a proper reasoning. Thanks though

 

[ahmed butt]

I want a proper reasoning. Thanks though

which year is it? so i can explain better

 

[chocolatelover]

Is the answer A?
5/15*12 + 10/15*6 = 8 kPa

Yes it is. Thank you!

 

[The Sarcastic Retard]

which year is it? so i can explain better

I dont remember.

 

[nehaoscar]

I have relooked at the question and spotted my mistake.

The concentration of Fe2(SO4)3 is o.1 mol/dm3. But since we are using concentration of Fe3+ , we do need to multiply it by 2 as there are two Fe3+ ions for each Fe2(SO4)3.

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

 

[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-