Chemistry: Post your doubts here!

[Brisingr]

7 What is the volume of steam produced when 1.00 g of ice is heated to 323°C at a pressure of
101 kPa?
A 0.27 dm3 B 1.3 dm3 C 2.7 dm3 D 48 dm3
anyone?how to do this qs i use pv=nrt but still ans not matched.ans is c

 

[amina1300]

7 What is the volume of steam produced when 1.00 g of ice is heated to 323°C at a pressure of
101 kPa?
A 0.27 dm3 B 1.3 dm3 C 2.7 dm3 D 48 dm3
anyone?how to do this qs i use pv=nrt but still ans not matched.ans is c

Mass of 1 cm3 of steam (H20) = 1 g
Mol of H20 = 1g / 18 = 0.0555556
1 mol of H20 occupies 24dm^3 at 298K
0.0556 would occupy = 24 x 0.0556 = 1.33 dm^3
Volume of steam at 298K = 1.33 dm^3
Volume of steam at 1 K = 1.33/298 = 0.00446 dm^3
Volume of steam at 596 K = 0.00446 x 596 = 2.668 dm^3 ~ 2.67 dm^3

 

[Brisingr]

thankyou amina1300

 

[Holmes]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_11.pdf
Q4 I dont understand what Np Pu mean??
Q6 ??
Q17 ??
Q30??

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_13.pdf
Q9 ???
Q21 ??
Q33 Statement 2 ; No particles have zero energy at either temperature. ?? What does this mean in context?

Q4 I dont understand what Np Pu mean??

If you look at the periodic table: at the actinoids period you will find both
Np = NEPTUNIUM
Pu = PLUTONIUM

HOPE I HELPLED!

 

[darks]

It was tough paper *sigh*

Which paper pls?

 

[Holmes]

dummb me Im at my last Chem exam and I learn this now!!!!!!!
Any tips for tomorrows examm???

Tipssss!
Stay Calm and relaxed. My teacher advise me to solve the organic part of the paper before because that gives us confidence about the paper. If you are good at Organic then you can do the same.

 

[amina1300]

Tipssss!
Stay Calm and relaxed. My teacher advise me to solve the organic part of the paper before because that gives us confidence about the paper. If you are good at Organic then you can do the same.

I HATE ORGANIC CHEMISTRY I ALWAYS KEEP FORGETTING THE REACTIONS >_<

 

[Holmes]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_11.pdf
Q4 I dont understand what Np Pu means??
Q6 ??
Q17 ??
Q30??

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_13.pdf
Q9 ???
Q21 ??
Q33 Statement 2 ; No particles have zero energy at either temperature. ?? What does this mean in context?

 

[Holmes]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_11.pdf
Q4 I dont understand what Np Pu means??
Q6 ??
Q17 ??
Q30??

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_13.pdf
Q9 ???
Q21 ??
Q33 Statement 2 ; No particles have zero energy at either temperature. ?? What does this mean in context?

Q17 ??
CaCO3 + 2HCl ------> CaCl2 + CO2 + H2O
moles of HCl = (36*0.500)/1000
= 0.018 moles
Moles of CaCO3 = 0.009 moles
Mr of CaCO3 = 100
Mass of CaCO3 =100*0.009
= 0.9 g
% of CaCO3 in 2.00 g mass:
= (0.9/2) * 100
= 45%

Hope I helped

 

[amina1300]

These questions are explained on the previous pages

Thankyou Holmes

 

[amina1300]

INSHALLAH we all will get an A in Tomorrows Exam. Goodluck Everyone Adios .

 

[Holmes]

These questions are explained on the previous pages

Thankyou Holmes

Ok I didn't know.

 

[Holmes]

INSHALLAH we all will get an A in Tomorrows Exam. Goodluck Everyone Adios .

INSHALLAH

 

[Holmes]

I HATE ORGANIC CHEMISTRY I ALWAYS KEEP FORGETTING THE REACTIONS >_<

NO issue. Just stay confident that you know everything in the syllabus

 

[SohaibButt]

Which paper pls?

March 2016

 

[SohaibButt]

Can you tell the answers too plz.

25 B?
The one with Si02 and CO2 --> A?
Q32 D?

Ur ans r correct can u plz explain them?

 

[techgeek]

how are we supposed to know if the reaction is endothermic?

 

[Metallic9896]

View attachment 62483
how are we supposed to know if the reaction is endothermic?

Hmm if the solution does form that means water molecules felt more comfortable forming bonds with the anhydrous aluminium chloride than they did with themselves. All systems want to achieve a lower and lower energy state that gives out heat so they become more stable. If they DID like forming bonds with anhydrous aluminium choride, this means that the energy released when they formed these bonds was MORE than the energy needed to break the water molecules' bonds with themselves, which means that there was a net release of energy, i.e. reaction was exothermic, not endothermic. That leaves only C as the correct choice cause all other options contain statement 1 and we just got rid of it. Without even thinking about 2 and 3 you can choose C. But, you should know about 2 and 3 from the book and the chapter of periodicity where we are told to know reactions of water and period 3 chlorides. Hope I helped.

EDIT: Anything that successfully dissolves, you can be sure it's an exothermic process.

 

[darks]

Hmm if the solution does form that means water molecules felt more comfortable forming bonds with the anhydrous aluminium chloride than they did with themselves. All systems want to achieve a lower and lower energy state that gives out heat so they become more stable. If they DID like forming bonds with anhydrous aluminium choride, this means that the energy released when they formed these bonds was MORE than the energy needed to break the water molecules' bonds with themselves, which means that there was a net release of energy, i.e. reaction was exothermic, not endothermic. That leaves only C as the correct choice cause all other options contain statement 1 and we just got rid of it. Without even thinking about 2 and 3 you can choose C. But, you should know about 2 and 3 from the book and the chapter of periodicity where we are told to know reactions of water and period 3 chlorides. Hope I helped.

EDIT: Anything that successfully dissolves, you can be sure it's an exothermic process.

So i gave the wrong answer my prep not looking too good :/ You explained really well here.

 

[sarmadimran]

anyone plz