Chemistry: Post your doubts here!

[xhizors]

OHMYGOSH GUYS READ THE QUESTION! And NO, in ER it says B*0.1/20
-BECAUSE Succinic Acid is a DICARBOXYLIC ACID one mole reacts with 2 MOLES of NaOH so we divide my 2 according to the Equation.

thanks for the fact, only more able candidate can observe it nd u did too

 

[xhizors]

OHMYGOSH GUYS READ THE QUESTION! And NO, in ER it says B*0.1/20
-BECAUSE Succinic Acid is a DICARBOXYLIC ACID one mole reacts with 2 MOLES of NaOH so we divide my 2 according to the Equation.

whats the second column heading ??

 

[MaxStudentALevel]

thanks for the fact, only more able candidate can observe it nd u did too

No problem! And not at all, just read the question verrrrrry carefully!

 

[MaxStudentALevel]

whats the second column heading ??

I think C*0.02/50 !!

 

[xhizors]

I think C*0.02/50 !!

ok thanks !!

 

[knowitall10]

thanks for the fact, only more able candidate can observe it nd u did too

She's Pakistani

 

[Areeb Afzaal]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w09_qp_51.pdf
AoA,in q2 cant i subtract excess zinc and mass of tube from the mass of tube to obtain the excess zinc i.e D-A?

 

[applepie1996]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w09_qp_52.pdf
question 1 D
xhizors
MaxStudentALevel

 

[Areeb Afzaal]

The question says that NaOH should be in excess so the acid must be less than 0.06 mol.
Make any arrangment but the volume of all acids must stay constant eg 25 cm3 and 2 moldm.
Dibasic acids such as H2So4 dissociate two H ions so their cocentration should be further half than monobasic acids..
ahope u get that

 

[applepie1996]

The question says that NaOH should be in excess so the acid must be less than 0.06 mol.
Make any arrangment but the volume of all acids must stay constant eg 25 cm3 and 2 moldm.
Dibasic acids such as H2So4 dissociate two H ions so their cocentration should be further half than monobasic acids..
ahope u get that

Jazak Allah
i get it
but what i want to ask is soo for the dibasic acid i will use concentration as 1 moldm^-3 ?

 

[meobunny]

Don't worry, it'll happen. Keep faith in Allah and pray a lot, there're still 10 days 15 days to p4, revise only the group chemistry and the organic of AS, not the whole syll really. InshAllah, we'll pass

Insha Allah andnthat too with great marks Ameen ! So which group do i need to stress upon ? And could you help me with paper 5 chemistry and physics best tips ? Like best ones?

 

[Areeb Afzaal]

Jazak Allah
i get it
but what i want to ask is soo for the dibasic acid i will use concentration as 1 moldm^-3 ?

actlyyes exactly!

 

[Sana101]

Paper 5 May June 10 52
Can someone please tell me how to make the molal solutions. Question 1 part d)
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s10_qp_52.pdf

 

[xhizors]

Paper 5 May June 10 52
Can someone please tell me how to make the molal solutions. Question 1 part d)
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_52.pdf

(mol of a solid)x1000/mass of water

 

[applepie1996]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w09_qp_51.pdf
AoA,in q2 cant i subtract excess zinc and mass of tube from the mass of tube to obtain the excess zinc i.e D-A?

ummmm no you can't :/
because you have to find the mass of zinc used up

 

[Areeb Afzaal]

ummmm no you can't :/
because you have to find the mass of zinc used up

Can u explain..i thought that excees of zinc will react so found tht one

 

[applepie1996]

Can u explain..i thought that excees of zinc will react so found tht one

excess if zinc is added to make sure that all the traces of zinc iodide is removed from the test tube
so basically you're just finding the amount of zinc that reacted with the iodine

 

[imperial]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w08_qp_2.pdf

3c (ii)

What is meant by half-equations?

 

[Dukeofwin]

Can someone tell me What is the drama of 4s shell being filled before 3d? And to what elements? I've read about it but it's so confusing.

 

[Gémeaux]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w08_qp_2.pdf

3c (ii)

What is meant by half-equations?

Full equation is for the cell (after the cancelling of electron etc). Half equations are separate equations for each the anode and the cathode.
In this question that you have mentioned, only the equation from cathode is enough i.e.
2H+ + 2e–→ H2, and this leaves OH- ions in the remaining solution.