IGCSE Physics and Chemistry post your doubts !:)

[Manobilly]

It will help me and you !

 

[GriM ReapeR]

oookkk i have a (lot) of doubts in physics.. but chemistry first...
in electrolysis of aqueous and concentrated aqueous substances.. what do we have to remember to answer da questions? like what are the conditions??

 

[Manobilly]

For aqueous It is going to produce gases at anodes and cathodes.Like for electrolysis of water ,It will be 4OH Into 2 water and and 2 Hydrogen and oxygen ,O2 and anode ,hydrogen at cathode.For NaCl it gives hydrogen at cathode and chlorine at anode ,while the solution becomes NaOH.Remember hydrogen is always formed at cathode.
You have to remember the equations at both anodes and cathode to answer as they might ask a question about it.

Also if you have doughts in physics I would love to answer and any further in Chemistry,dont hesitate and ask

 

[Tommi]

for me its the calculations!

 

[GriM ReapeR]

thank you so much! haha i was getting confused there for a while.. ok, i have this huge doubt in stoichiometry (is that how you spell it?) that i cant even begin to explain. im very confused with all the formulas. I've tried reading on google but i cant understand anything. this topic sort of scares me (haha).
and in physics, what is the relation between current, potential difference, resistance, capacitance, power, and energy? (in the circuits chapter) this also confuses me alot :/

thank you soo much in advance

 

[Manobilly]

thank you so much! haha i was getting confused there for a while.. ok, i have this huge doubt in stoichiometry (is that how you spell it?) that i cant even begin to explain. im very confused with all the formulas. I've tried reading on google but i cant understand anything. this topic sort of scares me (haha).
and in physics, what is the relation between current, potential difference, resistance, capacitance, power, and energy? (in the circuits chapter) this also confuses me alot :/

thank you soo much in advance

Okey what questions do you have in stoichiometery tell me past paper questions ?the more you will practice them the more you will be a pro in them so tell me so I can help you solve them. When do you have your chemistry paper 3?Let me know as I have it on the 30th of May and I will be free on 25th May, so I will be available to answer your question from 25th May for chemistry.For physics let me know your doubts in details so it is easy for me to do so as I have my exam on 25th may.

Voltage is proportional to current. Voltage is the energy provided to the circuit ,current is total electrons and charge flowing into the circuit.Resistance is Voltage divided by current,Resistance is a physical quantity that is used to limit the current.Capacitance ,there is nothing like this in the igcse syllabus except for capicators. Power is The total power so it is Voltage * Current, and there is 1 more formula for Power it is energy transformed/time. Energy is energy needed so it is Power* time or in simple it can be regarded as Voltage *Current *Time.As you know Power is Voltage * Current.

Your welcome.I will welcome your more doubts if you have. Good Luck!

 

[Manobilly]

for me its the calculations!

Let me know the questions ,as you solve them you will be a pro.Solve questions.Let me know on 25th may as I have my exam on 30th may for chem ,so it will be easy for me,When do you have your exam?

 

[sweetsis]

do u have any last minute tips for phys exam ????

 

[Mystery]

Physics: when temperature is increased, volume is also increased but pressure is kept constant........how can pressure be kept constant because when temperature is increased the gas molecules will hit the molecules with greator force so eventually pressure would be increased......how can pressure be kept constant??

 

[Z.A.M]

Physics: when temperature is increased, volume is also increased but pressure is kept constant........how can pressure be kept constant because when temperature is increased the gas molecules will hit the molecules with greator force so eventually pressure would be increased......how can pressure be kept constant??

Temperature is the average kinetic energy of molecules so if temp increases kinetic energy of molecules increases and thus because the molecules move with greater speed so the number of collisions increases this is how the pressure increases clear this concept first
Now coming to ur question imagine u have a container which contains air molecules when the temp increases the volume increases but the pressure remains the same because since the volume has increased the space between the container has increased so now although the speed of the molecules has increased it will take more time for the molecule to travel from one wall to the other so the number of collision will decrease and hence the pressure will remain the same
Hope u get it

 

[Z.A.M]

oookkk i have a (lot) of doubts in physics.. but chemistry first...
in electrolysis of aqueous and concentrated aqueous substances.. what do we have to remember to answer da questions? like what are the conditions??

Sometimes we have two type of catios and anions migrating to the cathode so preferential dicharge takes place
For cations always remember the less reactive metal will gain electron easily and be deposited for e.g electrolysis of Aqueous Nacl we have Na and H ions H will be discharged to hydrogen gas
Then for anions the pereferential discharge depends on two things
1 Concentration:
For eg in electrolysis of Concentrated Nacl we have OH and Cl ions migrating topwards anode but Cl ions will be discharged because there more in number coz its concentrated
2Type of electrode
Hope u get it

 

[Mystery]

Temperature is the average kinetic energy of molecules so if temp increases kinetic energy of molecules increases and thus because the molecules move with greater speed so the number of collisions increases this is how the pressure increases clear this concept first
Now coming to ur question imagine u have a container which contains air molecules when the temp increases the volume increases but the pressure remains the same because since the volume has increased the space between the container has increased so now although the speed of the molecules has increased it will take more time for the molecule to travel from one wall to the other so the number of collision will decrease and hence the pressure will remain the same
Hope u get it

thnnx alot......can u plz solve and explain q.5 of http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w11_qp_32.pdf

 

[Z.A.M]

thnnx alot......can u plz solve and explain q.5 of http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w11_qp_32.pdf

First of all Thanku for asking this question it was a nice one since I was just revising this chapter

 

[Z.A.M]

Now for your answer Mystery
U see conduction always occurs in solids seeing the picture the have labelled copper so you know metals are good conductors of electricity so The copper rod will absorb the heat and conduct all the heat away quickly
Then Convections always happens in liquids or air So the Fins would be the feature because they have gaps of air between them through which heat will escape by convection
For radiation u see black surfaces are good absorbers of heat which means in turn they must also be good emitters of heat right?
So it's going to be the fins again
Hope u get it please ask anything u dont

 

[GriM ReapeR]

Sometimes we have two type of catios and anions migrating to the cathode so preferential dicharge takes place
For cations always remember the less reactive metal will gain electron easily and be deposited for e.g electrolysis of Aqueous Nacl we have Na and H ions H will be discharged to hydrogen gas
Then for anions the pereferential discharge depends on two things
1 Concentration:
For eg in electrolysis of Concentrated Nacl we have OH and Cl ions migrating topwards anode but Cl ions will be discharged because there more in number coz its concentrated
2Type of electrode
Hope u get it

thank you very much! it really helps

 

[Z.A.M]

thank you very much! it really helps

Welcome nytime dude

 

[Z.A.M]

Guys 2 questions for all of u :
1. What were the most difficultEST Toughest papers for Chemistry P3 IGCSE
2. What were the most difficultEST Toughest papers for Physics P6 IGCSE
Plx all of u do answer
Thanx in advance

 

[Manobilly]

There isnt any tough one ,I havent come over any tough one Alhamdulillah but I dont know

 

[Arshan]

give me some notes for waves and forces, i am very weak in that.................................
I have my exams in next month!!!!!!!!!!!!!!!!!11

 

[somya]

give me some notes for waves and forces, i am very weak in that.................................
I have my exams in next month!!!!!!!!!!!!!!!!!11

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