Biology; Chemistry; Physics: Post your doubts here!

[étudiante]

Aa gai aqal?


Bat kis ki ho rahi hai? -.-

u just said hydrolysis sire

 

[Mayedah]

Aa gai aqal?


Bat kis ki ho rahi hai? -.-

I have the concepts of organic well!! U mentioned esters hydrolysis in naoh presence just which means dat the reaction will produce an alcohol and the carboxylic acid !!

 

[étudiante]

I have the concepts of organic well!! U mentioned esters hydrolysis in naoh presence just which means dat the reaction will produce an alcohol and the carboxylic acid !!

alrught alright! Chill

 

[Tharindu]

It's confusing
Current decreases when Resistance increase.
And yes, voltage increase then current decreases.

Isn't voltage directly proportional to the current

 

[SalmanPakRocks]

Thank Allah I wasn't even there

Isn't voltage directly proportional to the current

Well I used the theory that why is power transmitted over high voltage? That's cuz high voltage means less current, isn't that right?

 

[bogus]

its there in the Xtreme Revision section...




Mods please look to it...

people one point... in the series combination of resistors greater the resistance greater the voltage across it so voltage divides proportionally

 

[bogus]

in mentioned case ... when resistance is increased,voltage should be increased if it would not be constant!! In this case just current would decrease, keeping the equation valid!! i.e v=ir , r increased therfore i decrease so v = same(6 volts)!!!!!

dude total voltage doesnt change... it divides proportionally across each resistor so if one resistor is 20 and the other 30 ohm voltage divides in the ratio 2:3... same is the case with a potential divider

 

[bogus]

whats the unit for the sample..

grams.... duh.. done this question a million times

 

[bogus]

A 0.50 sample of vegetable oil reacted with 60cm^3 of hydrogen,measured at r.t.p
Assuming tht one molecule of the oil contains only one double bond calculate the relative molecular mass of the oil !

so the mole ratio will be 1:1 so 60/24 whatever that gives is the number of moles of the sample as well as one double bond means all of h2 reacted so then divide 0.5 by the number of moles. (in easy words one double bode consumes one h2 molecule so mole ratio is one ratio one) Not at all rocket since

 

[khizer shahab]

dude total voltage doesnt change... it divides proportionally across each resistor so if one resistor is 20 and the other 30 ohm voltage divides in the ratio 2:3... same is the case with a potential divider

thats what i m saying !!!!

 

[aj shahzad]

how to prepare for chemistry and physics in the last 15 days before exams ?

 

[Mayedah]

http://www.xtremepapers.com/papers/...nal O Level/Physics (5054)/5054_s10_qp_12.pdf
Mcq no 11
The answer is D ..i wanna know y isnt it C :/

 

[GetSomeLife]

I have the concepts of organic well!! U mentioned esters hydrolysis in naoh presence just which means dat the reaction will produce an alcohol and the carboxylic acid !!

Yes sure... whatever keeps you happy... you don't have to get all mad

Isn't voltage directly proportional to the current

Well I used the theory that why is power transmitted over high voltage? That's cuz high voltage means less current, isn't that right?

We use the POWER equation when speaking if transmission cables. I.E. I = P/V
Notice that, in this equation, Current is INVERSELY proportional to voltage.

In simple circuits, we use I = V/R where I is directly proportional to the voltage.

so the mole ratio will be 1:1 so 60/24 whatever that gives is the number of moles of the sample as well as one double bond means all of h2 reacted so then divide 0.5 by the number of moles. (in easy words one double bode consumes one h2 molecule so mole ratio is one ratio one) Not at all rocket since

Method is right but the 60 cm^3 won't be changed to dm^3 by the examiner

thats what i m saying !!!!

 

[JojiKhan]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_s10_qp_12.pdf
Mcq no 11
The answer is D ..i wanna know y isnt i

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_s10_qp_12.pdf
Mcq no 11
The answer is D ..i wanna know y isnt it C :/

This is because as P=F/A thus Pressure is inversely proportional to area. In C the graph is not that of inverse proportionality and in D it is........ So D is the answer..

 

[Mayedah]

Yes sure... whatever keeps you happy... you don't have to get all mad




We use the POWER equation when speaking if transmission cables. I.E. I = P/V
Notice that, in this equation, Current is INVERSELY proportional to voltage.

In simple circuits, we use I = V/R where I is directly proportional to the voltage.


Method is right but the 60 cm^3 won't be changed to dm^3 by the examiner

Haha wasnt mad at all. I had sme misunderstandings tht got cleared last night : D thnx anyway !

 

[GetSomeLife]

Haha wasnt mad at all. I had sme misunderstandings tht got cleared last night : D thnx anyway !

Got cleared? So, what was your answer?

 

[ayeshaK]

Explain mcq no 18 and 22 please !!
http://www.xtremepapers.com/papers/...onal O Level/Biology (5090)/5090_w07_qp_1.pdf

 

[Mayedah]

Got cleared? So, what was your answer?

Actually i didnt read tht u asked hydrolisis by naoh .i jst wrote the answer ,hydrolisis of ester by h2o
Ester + naoh = alcohol + ester salt
Ester + h20 = alcohol + carboxylic acid

 

[GetSomeLife]

Actually i didnt read tht u asked hydrolisis by naoh .i jst wrote the answer ,hydrolisis of ester by h2o
Ester + naoh = alcohol + ester salt
Ester + h20 = alcohol + carboxylic acid

Alhamdulillah

 

[étudiante]

Actually i didnt read tht u asked hydrolisis by naoh .i jst wrote the answer ,hydrolisis of ester by h2o
Ester + naoh = alcohol + ester salt
Ester + h20 = alcohol + carboxylic acid

wat else was i trying 2 tell u last night miss?
neways... good u got it now