Physics, Chemistry and Biology: Post your doubts here!

[DANISH182]

Show us some facts about the method used in the question? (Screenshot the question only)
Stop writing in CAPS ITS ANNOYING!!

didn't understand ur question what r utrying so say?

 

[DANISH182]

guys the last question in p62 chemistry is always about planning an investigation and is difficult for me so guys some good tips u can give me

thnx in advance

 

[DANISH182]

i am not getting my answers guys!!!!!!!!!!!!!!!!!!!!!!!!

 

[sj0007]

umm...... so I am having a problem in answering the questions where we have to write which is more concentrated based on the volumes of the substances in chem paper 6
How do we know that the substance was supposed to be more concentrated because more amount volume is used or the substance was less concentrated because more volume was used?
Can anybody plz help me out? Thnx...............

 

[XxChampXx]

umm...... so I am having a problem in answering the questions where we have to write which is more concentrated based on the volumes of the substances in chem paper 6
How do we know that the substance was supposed to be more concentrated because more amount volume is used or the substance was less concentrated because more volume was used?
Can anybody plz help me out? Thnx...............

There are two scenarios for this:-

1) Check this paper first(MJ2011 QP61 Q4 e(iii)):- https://drive.google.com/folderview...sp=drive_web&tid=0BzumkDfi9230ajBJb1BVUl8xODg

So in this case the student is pouring solution(for which concentration is being checked) of potassium manganate(VII) from the beaker. Thus, the lesser the volume required for the colour to change, the more concentrated it is.

2)https://drive.google.com/folderview...drive_web&tid=0BzumkDfi9230ajBJb1BVUl8xODg(MJ 2008 QP6 Q4 e(iii))

So in this case the solution for which concentration is being checked is not poured, the known volume is already in the flask. Thus, whatever is being poured, in this case potassium manganate(VII), has to be in larger volume.

So basically you just have to look if the solution checked for concentration(i.e. A and B) has a known volume or not. If it does not, then the one with the smaller difference is more concentrated. If it does have a known volume, then one with larger difference is more concentrated.

Good luck for your exams

 

[The_Boss]

i am not getting my answers guys!!!!!!!!!!!!!!!!!!!!!!!!

Screenshot the first part of question.

 

[Muaaz Iqbal]

Dude you are probably gonna give Islamiyat next year !! Then I 'll ask from ya !!!!

Who's Gonna Give it Next year I'm Giving it In Oct-November

 

[Saad the Paki]

So in the marking scheme they say:
"Heat for specified time,record temp, greatest temp rise better fuel"
I wrote :
"Heat till boiling point of 100°C, record time taken, less time taken better fuel"
Is this acceptable?

 

[UsamaFTW]

Guys for paper 0620/62/O/N/12 Question 5 (j) the marking scheme says any transition metal but copper, why not copper?

 

[My Name]

So in the marking scheme they say:
"Heat for specified time,record temp, greatest temp rise better fuel"
I wrote :
"Heat till boiling point of 100°C, record time taken, less time taken better fuel"
Is this acceptable?View attachment 53484

Nope.Why would you want to boil it till 100°C?
Do you know you are just burning the fuel?
The fuel when burned gives energy, that heats the water,so the fuel that shows more rise in temperature is a better fuel.

(You can take a look at this if you like
https://www.xtremepapers.com/commun...t-your-doubts-here.11053/page-420#post-916013)

 

[Manisha98]

i need chemistry p6 notes as soon as possible

 

[Mr.Physics]

Who's Gonna Give it Next year I'm Giving it In Oct-November

LOL 3 months main tyari kray ga !! it would be a miracle !! Waissay paper 2 bhi ho gya aaj !! Acha huwa alhamdulillah !! A* PAKKA INSHALLAH

 

[Saad the Paki]

LOL 3 months main tyari kray ga !! it would be a miracle !! Waissay paper 2 bhi ho gya aaj !! Acha huwa alhamdulillah !! A* PAKKA INSHALLAH

Not giving paper 3?

 

[Mr.Physics]

Not giving paper 3?

Lol i was talking about islamiyat !! was replying to ma pal Muazz !!

 

[Mr.Physics]

Not giving paper 3?

LOL who wants a C by doing core LOL

 

[Saad the Paki]

LOL who wants a C by doing core LOL

lol true that..!

 

[Saad the Paki]

To distinguish between water and ethanol:
Test : Add magnesium
Water: Bubbles of Hydrogen
Ethanol: No reaction
Acceptable?

 

[Muaaz Iqbal]

LOL 3 months main tyari kray ga !! it would be a miracle !! Waissay paper 2 bhi ho gya aaj !! Acha huwa alhamdulillah !! A* PAKKA INSHALLAH

JO smjhna hay Smj loo
Inshallah Ho jai gaa

 

[The_Boss]

To distinguish between water and ethanol:
Test : Add magnesium
Water: Bubbles of Hydrogen
Ethanol: No reaction
Acceptable?

No ethanol reacts with magnesium as magnesium is more reactive than the Hydrogen so displaces it.
Ethanol + Magnesium ---> Magnesium Ethoxide + Hydrogen (Not sure of spelling though)
A better test would be B.P Ethanol more volatile than water
Chemical test would be test pH using "pH meter" and water would have neutral and ethanol more alkaline. Write meter as it would be able to detect slight alkaline solution as well

 

[Abdurrahmanmuhammed]

No ethanol reacts with magnesium as magnesium is more reactive than the Hydrogen so displaces it.
Ethanol + Magnesium ---> Magnesium Ethoxide + Hydrogen (Not sure of spelling though)
A better test would be B.P Ethanol more volatile than water
Chemical test would be test pH using "pH meter" and water would have neutral and ethanol more alkaline. Write meter as it would be able to detect slight alkaline solution as well

ph meter not possible as both are neutral so cant distinguish but for ethanol and ethanoic acid ph meter is possible!