Biology; Chemistry; Physics: Post your doubts here!

[fatima0000]

is there any key for imran merchat's chem atp guess paper???

 

[usama321]

okay.....the question says that the solution T is made by dissolving the mixture R with 100 cm3 acid and then made upto 250 cm3 with distill water, both of which (acid & water) are colourless.
so even if a colour of Fe2+ or Fe3+ had exist, it will eventually fade to colourless.
the question is from june 06 Q-9...mark scheme says two option for (d) (i), colourless or green.
i am not sure why green is allowed but red-brown (Fe3+) is not, but you can always go with colourless...
hope it helps

actually i think mark scheme also allows yellow, and the Fe3+ ions are yellow in water, so all three of them should be correct, colorless, green and yellow

 

[chocolate_girl]

Do we get a periodic table in chem atp?

 

[Kamihus]

Do we get a periodic table in chem atp?

nope and you dont need it the Mr required will be given

 

[zuraiz]

I don't have lab waiting for me at home. How am I supposed to practice the PRACTICAL with past papers?! DO you have ATP or the real one?

ohhh i thought u were talking about P4

 

[ZaqZainab]

Marking scheme for 5070/04 o/n 2003
Please

 

[chocolate_girl]

Marking scheme for 5070/04 o/n 2003
Please

No ms are available on xtremepapers n probably anywhere else for 2003 and before, they are from 2004 and onwards

 

[usama321]

No ms are available on xtremepapers n probably anywhere else for 2003 and before, they are from 2004 and onwards

Marking scheme for 5070/04 o/n 2003
Please

check the examiner report instead

 

[ZaqZainab]

check the examiner report instead

okay

 

[flaminheroes]

Sodium Chloride is the ONLY exception to that rule. conc/dilute doesn't matter, chlorine will be discharged in both cases. the reason is kinda high level to understand, but in simple terms, it is due to the small size of NaCl lattice

wait that doesnt make sense. In my book Oxygen gas was released :/

 

[usama321]

wait that doesnt make sense. In my book Oxygen gas was released :/

Sodium Chloride is the ONLY exception to that rule. conc/dilute doesn't matter, chlorine will be discharged in both cases. the reason is kinda high level to understand, but in simple terms, it is due to the small size of NaCl lattice

k mercedes, pls don't misguide people. I assure you, in dilute NaCl, oxygen is produced at the positive electrode.

 

[ZaqZainab]

I wanna know about the difference between concentrated,Dilute,Concentrated Aqueous,Molten,Dilute concentrated aqueous electrolysis there differences...
Can 2 gases be formed on ONE electrode?for example oxygen and chlorine at anode possible?
Thank yew

 

[flaminheroes]

I wanna know about the difference between concentrated,Dilute,Concentrated Aqueous,Molten,Dilute concentrated aqueous electrolysis there differences...
Can 2 gases be formed on ONE electrode?for example oxygen and chlorine at anode possible?
Thank yew

https://sites.google.com/site/urbangeekclassroomsg/chemistry-classroom/electrolysis

 

[usama321]

I wanna know about the difference between concentrated,Dilute,Concentrated Aqueous,Molten,Dilute concentrated aqueous electrolysis there differences...
Can 2 gases be formed on ONE electrode?for example oxygen and chlorine at anode possible?
Thank yew

concentrated and aqueous concentrated are the same thing, it means that there is large ammount of the solute i.e NaCl in the water. Dilute or dilute aqueous means that there is a small ammount of NaCl in the water. Molten means that NaCl has been turned to its liquid state, and it does not contain any water.

No, two gases can't be formed on the same electrode. Although it can happen that one gas reacts with the electrode and make another gas like in aluminium electrolysis where oxygen is produced at the graphite cathode, reacts with it and makes carbon dioxide.

 

[flaminheroes]

k mercedes, pls don't misguide people. I assure you, in dilute NaCl, oxygen is produced at the positive electrode.

Exactly :/ i googled it even. Say's it releases H+. and there cant be a mistake in the marking scheme because the examinars report said the same -.-

 

[ZaqZainab]

concentrated and aqueous concentrated are the same thing, it means that there is large ammount of the solute i.e NaCl in the water. Dilute or dilute aqueous means that there is a small ammount of NaCl in the water. Molten means that NaCl has been turned to its liquid state, and it does not contain any water.

No, two gases can't be formed on the same electrode. Although it can happen that one gas reacts with the electrode and make another gas like in aluminium electrolysis where oxygen is produced at the graphite cathode, reacts with it and makes carbon dioxide.

Now from my point of view
1.the most water is in dilute concentrated or concentrated which is the same
2.the small amount of water is in dilute or dilute aqueous
3. NO water in Molten
Now what if it Just AQUEOUS nothing else does that mean a SMALL amount of water? Case you missed it i guess

 

[ZaqZainab]

and one more this when there is water in a electrolyte ALWAYS H+ at cathode and OH- at anode? I heard if there is a halogen then halogen is produced and not -OH is it true?

 

[ZaqZainab]

I am so annoying so sorry if i am wasting your time you can choose not answer i won't mind i have well appreciated your last answers

 

[flaminheroes]

Now from my point of view
1.the most water is in dilute concentrated or concentrated which is the same
2.the small amount of water is in dilute or dilute aqueous
3. NO water in Molten
Now what if it Just AQUEOUS nothing else does that mean a SMALL amount of water? Case you missed it i guess

no man you got it wrong. In dilute soloutions, water content is in a higher content.
Aqueous has a higher amount of water then in concentrated.

 

[usama321]

Now from my point of view
1.the most water is in dilute concentrated or concentrated which is the same
2.the small amount of water is in dilute or dilute aqueous
3. NO water in Molten
Now what if it Just AQUEOUS nothing else does that mean a SMALL amount of water? Case you missed it i guess

dilute concentrated is nothing, it is either dilute or concentrated. The rest you are right. About the last thing, they mostly mention whether it is concentrated or dilute, and i only see it rarely that they write only aqueous when talking about electrolysis.

and one more this when there is water in a electrolyte ALWAYS H+ at cathode and OH- at anode? I heard if there is a halogen then halogen is produced and not -OH is it true?

about your this question, i suggest you read the whole topic, as you don't seem to know the basics, and it is quite a long and important topic. So, please read this from the book and you will understand.