Biology; Chemistry; Physics: Post your doubts here!

[sufyanali12]

Assalam-o-Allaikum and Hi everyone ,
hope u all are doin great !

Well as the topic says help for chemistry biology and Physics is available here that means that u can ask any mind blowing question or ask any question regarding a particular topic or ask abt any questions from Past paper or any of your text books.

I made this topic so that people dont make many posts asking abt bio,physics or chemistry individually but they can post their reply here where it can be answered with ease and the members wont have to go searching for topics to help! !

So what are u waiting for now write ur questions here !
THANKS and Bye or Allah Hafiz ! :wink: :good:

i have a question please.
The chapter name is acids and bases it's like ... Oxides can be classified as acidic,basic,or amphoteric
(a)How can the calssification of oxides be related to their metallic and non-metallic character?

 

[scouserlfc]

i have a question please.
The chapter name is acids and bases it's like ... Oxides can be classified as acidic,basic,or amphoteric
(a)How can the calssification of oxides be related to their metallic and non-metallic character?

Actually this means that metallic elements like sodium and others will form basic oxides as they are good bases while non metallic elements like chlorine form acidic oxides and amphoteric oxides are like zinc and aluminum and some others which can be either basic or acidic ! ! ! ! At this level u really dont need any more details abt them just have the ability to specify thats all

What do you use to study? you really good at science subjects (Y)!

HAHAHAHA ! cmon im not that great im really average others are much better than me but they are i guess to selfish to help u all here

Thanks a lot..!!!!
And please let me know the last answer when u have found it. In fact, i remember noting this question down from a book in my school library so i guess its not out of syllabus.
In the meanwhile, can u pls explain question 5c(ii) of the IG paper I am uploading. I have my exams in two days so please help me out... Thanks again

As im in a hurry at this point i can t solve it but ill surely reply tomorrow

 

[Nerdz]

Can someone explain me the answer of question 11 and question 12 in Physics 5054 Paper 12 (mcq paper) REPLY ASAP! May June 2012 paper

 

[CaptainDanger]

^ Q11- Pressure = ρgh= 1000 × 10 × (20/100) = Answer

Q12- P1V1=P2V2

P1= P
V1= 200

P2=?
V2=200+100 = 300

Put and solve for the answer.

 

[Ray boodha]

I need biology paper 5090,, chemistry paper 5070,, and als0 physics 5054 for 0-level.......... if u have for may/ june 2012,, can u plz just share with me????????

 

[CaptainDanger]

I need biology paper 5090,, chemistry paper 5070,, and als0 physics 5054 for 0-level.......... if u have for may/ june 2012,, can u plz just share with me????????

May/June 2012 Question Papers + Marking Schemes + Grade Thresholds

 

[scouserlfc]

Thanks a lot..!!!!
And please let me know the last answer when u have found it. In fact, i remember noting this question down from a book in my school library so i guess its not out of syllabus.
In the meanwhile, can u pls explain question 5c(ii) of the IG paper I am uploading. I have my exams in two days so please help me out... Thanks again

Okay heres what i think happened
first the aqueous sulphur dioxide means Sulphate ion and Hydrogen ion are present in solution then after adding barium chloride and then bromine this happens the bromine forms HBr with the positive ion of H present and then Cl comes in a flurry displaces ir from its acid and forms its own and then seeing Barium empty Sulphate ion bonds with the barium producing a white ppt. of BaSO4. remember all things are dissolved in water so every element is in ion form and can react by itself

 

[smart_boy]

Okay heres what i think happened
first the aqueous sulphur dioxide means Sulphate ion and Hydrogen ion are present in solution then after adding barium chloride and then bromine this happens the bromine forms HBr with the positive ion of H present and then Cl comes in a flurry displaces ir from its acid and forms its own and then seeing Barium empty Sulphate ion bonds with the barium producing a white ppt. of BaSO4. remember all things are dissolved in water so every element is in ion form and can react by itself

Thanks..!
Here's another doubt...
Suggest a practical method by which the rate of reaction can be investigated in the following case: Nitrogen monoxide reacting with Oxygen.
I know that NO and O2 are colourless gases and the product of the reaction that is NO2, is a brown gas. Just tell me what can be done ahead...
2NO + O2 à2NO2

 

[scouserlfc]

Thanks..!
Here's another doubt...
Suggest a practical method by which the rate of reaction can be investigated in the following case: Nitrogen monoxide reacting with Oxygen.
I know that NO and O2 are colourless gases and the product of the reaction that is NO2, is a brown gas. Just tell me what can be done ahead...
2NO + O2 à2NO2

HMMM this is quite some question whatever ive done uptil now,all stuff is either solid or liquid and u cant use those methods for these gases i think wait ill probably reply in the night

 

[smart_boy]

HMMM this is quite some question whatever ive done uptil now,all stuff is either solid or liquid and u cant use those methods for these gases i think wait ill probably reply in the night

Pls let me know if u get d ans...
Till then pls help me out in electronics...
1. A simple moisture-warning circuit is shown in which the moisture detector consists of two closely spaced copper rods.
(a) Warning lamps are often placed in the collector circuit of a transistor. Why is a relay used here?

 

[Amnaa]

physics notes related to chapters current electricity, practical electricity and parallel and series circuits !!!1

 

[scouserlfc]

Thanks..!
Here's another doubt...
Suggest a practical method by which the rate of reaction can be investigated in the following case: Nitrogen monoxide reacting with Oxygen.
I know that NO and O2 are colourless gases and the product of the reaction that is NO2, is a brown gas. Just tell me what can be done ahead...
2NO + O2 à2NO2

the only way to do is basically to look up the concentration of NO2 using a suitable concentration detector,a stop watch is started as we commence the experiment and at particular intervals we record the time and concentration,taking multiple readings and then plotting a graph whose gradient gives us the rate of reaction I dont think that u have to worry abt rate of reaction of gases because u wont find it coming in O Levels

Pls let me know if u get d ans...
Till then pls help me out in electronics...
1. A simple moisture-warning circuit is shown in which the moisture detector consists of two closely spaced copper rods.
(a) Warning lamps are often placed in the collector circuit of a transistor. Why is a relay used here?

For this my friend ask in the IGCSE thread or probably in A level thread becuz since im the only living being on this thread and as i dont know the answer then u probably refer to A levels area were people will help u on these question on Electronics Sorry

 

[smart_boy]

the only way to do is basically to look up the concentration of NO2 using a suitable concentration detector,a stop watch is started as we commence the experiment and at particular intervals we record the time and concentration,taking multiple readings and then plotting a graph whose gradient gives us the rate of reaction I dont think that u have to worry abt rate of reaction of gases because u wont find it coming in O Levels




For this my friend ask in the IGCSE thread or probably in A level thread becuz since im the only living being on this thread and as i dont know the answer then u probably refer to A levels area were people will help u on these question on Electronics Sorry

Are u feeling tired of helping me out in my questions..?? I m not evn asking sumthng out of syllabus..!! And its ok if u dont know the answer.. At least keep helping me out in whatever u can.. I guess u r d only SMART guy out here..! And i need ur help cos i m not..!! (dont go by my profile name..!! )

 

[KyleoAhsan]

To be honest I have never seen those questions on past papers too! So I am not answering, anything from O levels me and scouserlfc will help! !

 

[scouserlfc]

Are u feeling tired of helping me out in my questions..?? I m not evn asking sumthng out of syllabus..!! And its ok if u dont know the answer.. At least keep helping me out in whatever u can.. I guess u r d only SMART guy out here..! And i need ur help cos i m not..!! (dont go by my profile name..!! )

Dude not tired at all,its simply i left out the electronics section which was titled as basic in the syllabus becuz they said we will include a question in option for this so i was always safe so i have no idea abt transistors,astable and bistable crap
any other questions like on thermistors or other stuff on electricity i can answer but not this

 

[scouserlfc]

To be honest I have never seen those questions on past papers too! So I am not answering, anything from O levels me and scouserlfc will help! !

Just to let u know this is in the O levels syllabus but i think its an option still so u can always leave this part its a little difficult

 

[KyleoAhsan]

Just to let u know this is in the O levels syllabus but i think its an option still so u can always leave this part its a little difficult

Oh well, Obviously not seen in GCSE O level (Y)! I am pretty sure I was never taught about it O: ~

 

[scouserlfc]

Oh well, Obviously not seen in GCSE O level (Y)! I am pretty sure I was never taught about it O: ~

thats just becuz its a pretty tough topic and even in A levels its not there so no point teaching something which wont help later waste of time and strength

 

[MuslimGirl]

can any1 suggest me the best buks available for physics chemistry and bio? im using matters for physics and chemistry and the oxford biology for o levels by marry jones...nd i find all three of them useless...

Biology matters is good....
and for other just take the one which have name "Chemistry for o-levels" < (it has green color..) and for physics take he one which have name "Physics for o-levels" i am not sure about the names of writers....i'll be chking them and will be telling to you soon Insha'Allah

 

[smart_boy]

Dude not tired at all,its simply i left out the electronics section which was titled as basic in the syllabus becuz they said we will include a question in option for this so i was always safe so i have no idea abt transistors,astable and bistable crap
any other questions like on thermistors or other stuff on electricity i can answer but not this

Ok... Thanks... I need your help again.. I am posting a pic of a question.. The ans is D in the marking scheme but i cant understand whats the logic behind it.. Pls hav a look and help me if you know...