Chemistry: Post your doubts here!

[Tessa Grey]

I need help. I can't understand these two MCQs. i) Which of the enthalpy changes of the following reactions can only be obtained by Hess's law. 1 The hydration of anhydrous copper sulphate to form crystals of CuSO4.5H2O 2. The formation of methane from its elements 3. The combustion of glucose, C6H12O6 ii) Sodium ions can be formed from sodium atoms. Na(s) ---> Na+(g) Which quantities are required to calculate the enthalpy change of formation of gaseous sodium ions? 1 enthalpy change of atomisation of sodium 2 first ionisation energy of sodium 3 enthalpy change of formation of sodium.

The answer for the first question is C, 2 and 3 are correct.

 

[smiling star]

Can someone explain these two Mcqs please?

 

[Thought blocker]

Can someone explain these two Mcqs please?

which?

 

[i_try9621]

Need help with this

 

[selrey]

View attachment 61502 Need help with this

Ans is D. Since NH4+ ion acts as a proton donor it means NH4Cl is acid and MgOH is basic. So neutralization will occur

 

[i_try9621]

Ans is D. Since NH4+ ion acts as a proton donor it means NH4Cl is acid and MgOH is basic. So neutralization will occur

Thanks

 

[i_try9621]

Need help with this one. Shouldn't the answer be C? ( Ans is B)

 

[DragonCub]

View attachment 61504 Need help with this one. Shouldn't the answer be C? ( Ans is B)

The work and answer are shown in the image.




A simpler way to think is that no matter how much R is generated, the amount of P + Q always stays at 2.
Therefore, the amount of P consumed must equal the amount of Q generated. This means P and Q have the same stoichiometric coefficient.

Again, this leads to Option B.

 

[i_try9621]

The work and answer are shown in the image.

View attachment 61505


A simpler way to think is that no matter how much R is generated, the amount of P + Q always stays at 2.
Therefore, the amount of P consumed must equal the amount of Q generated. This means P and Q have the same stoichiometric coefficient.

Again, this leads to Option B.

Wow you made it look much easier than what I had tried. Thanks!

 

[krishnapatelzz]

Can anyone explain this question and solve?

this is very easy question... 10th grade physics ,,, q = mass x specific heat capacity x change in temperatue

 

[i_try9621]

Need Help ples
It's from 9701/04/O/N/04

 

[Albert Lianto]

View attachment 61520 Need Help ples
It's from 9701/04/O/N/04

Sorry the workings got condensed by the end.

http://imgur.com/gYjLLR2

 

[i_try9621]

Sorry the workings got condensed by the end.

http://imgur.com/gYjLLR2

No problem, I am happy that you helped and I understood it

 

[Need A*]

Inorganic Chem is so HARD !!!!!!!
does any one of u have inorganic notes ??
and I am attaching list of organic reactions ... if any of u need it

 

[Thought blocker]

Inorganic Chem is so HARD !!!!!!!
does any one of u have inorganic notes ??
and I am attaching list of organic reactions ... if any of u need it

You just need to refer your textbook. It has all fruitful notes. Everything is covered in textbook. Have you read it all?

 

[Thought blocker]

Inorganic Chem is so HARD !!!!!!!
does any one of u have inorganic notes ??
and I am attaching list of organic reactions ... if any of u need it

https://www.xtremepapers.com/commun...αтι¢ѕ-ѕ¢αηηє∂-ρυяє-мαтн-вσσкѕ-υρℓσα∂є∂.33891/

In chemistry section with blue ink, you can find your notes there. ^_^
good luck.

 

[Need A*]

You just need to refer your textbook. It has all fruitful notes. Everything is covered in textbook. Have you read it all?

yep and still it confusing .....

https://www.xtremepapers.com/community/threads/вєѕт-яєνιѕιση-яєѕσυя¢єѕ-ƒσя-ρнуѕι¢ѕ-¢нємιѕтяу-αη∂-мαтнємαтι¢ѕ-ѕ¢αηηє∂-ρυяє-мαтн-вσσкѕ-υρℓσα∂є∂.33891/
View attachment 61539
In chemistry section with blue ink, you can find your notes there. ^_^
good luck.

thanks a lot .... I check it out ...

 

[areeba240]

does anyone have cie nov. 2016 paper?

 

[Thought blocker]

does anyone have cie nov. 2016 paper?

http://papers.gceguide.com/A Levels/Chemistry (9701)/

 

[areeba240]

5(ii) pzz help