Chemistry: Post your doubts here!

[Casablanca]

Can anyone please tell me how we improve experiments? Like covering solutions, taking more readings etc.
Thanks

For enthalpy experiments, use insulating material, and use an electronic thermometer that takes more accurate readings.
For titration, take multiple titration readings, and if there's anything interfering with the titration, get rid of it somehow (by heating, or filtering if it is a solid, etc...)
For salt analysis there is the most. If there is a color change involved, use a colorometer instead of eyes. If there is a gas produced, use a white background to notice it, and note the smell. If there is heating involved, make sure no heat is lost, etc... You can even make up your own.

---

What does an amorphous solid look like? Will we ever be given one, or will we always be given crystalline solids to identify?

 

[iKhaled]

i just wanna ask, when u r given concentration in g/dm^3 how can u change it into moles/dm^3 ?

 

[hmlahori]

i just wanna ask, when u r given concentration in g/dm^3 how can u change it into moles/dm^3 ?

just find the number of moles from the grams of the given substance in 1 dm3 and u get mol/dm3 thats it!

 

[umarashraf]

i just wanna ask, when u r given concentration in g/dm^3 how can u change it into moles/dm^3 ?

multiply the denominator by the Mr of the that substance and YOu will have mol per dm Cube....

 

[Goku]

Any tips for practicals?

 

[iKhaled]

what's a chemical test for ammonia gas?

 

[iKhaled]

i need someone to show me how to draw the neutralization graph :/

 

[Tazyeen K]

what's a chemical test for ammonia gas?

Ammonia turns damp red litmus paper blue.

 

[iKhaled]

Ammonia turns damp red litmus paper blue.

is that a chemical test?

 

[Tazyeen K]

is that a chemical test?

Wats a chemical test??

 

[Soldier313]

u just divide the mass by the molar mass of the substance to get the moles......so for example we are talkin about the concentration of HCl is let's say 3.65g/dm3 so u divide 3.65 by the Mr which is 36.5 and you get your conc as 0.1mol/dm3......hope you understood...

 

[Soldier313]

u just divide the mass by the molar mass of the substance to get the moles......so for example we are talkin about the concentration of HCl is let's say 3.65g/dm3 so u divide 3.65 by the Mr which is 36.5 and you get your conc as 0.1mol/dm3......hope you understood...

 

[iKhaled]

u just divide the mass by the molar mass of the substance to get the moles......so for example we are talkin about the concentration of HCl is let's say 3.65g/dm3 so u divide 3.65 by the Mr which is 36.5 and you get your conc as 0.1mol/dm3......hope you understood...

do uk how to draw the straight line of neutralization on the graph? pls help me

 

[Soldier313]

u just divide the mass by the molar mass of the substance to get the moles......so for example we are talkin about the concentration of HCl is let's say 3.65g/dm3 so u divide 3.65 by the Mr which is 36.5 and you get your conc as 0.1mol/dm3......hope you understood...

 

[Soldier313]

http://www.docbrown.info/page12/gifs/pHgraphnotes.gif
http://www.wiley.com/college/pratt/0471393878/student/review/acid_base/buffer_titration.gif

i got these from google...chek em out
but we havent done these sort of things at xul so i m not sure how to do it...sorry:/

 

[iKhaled]

http://www.docbrown.info/page12/gifs/pHgraphnotes.gif
http://www.wiley.com/college/pratt/0471393878/student/review/acid_base/buffer_titration.gif

i got these from google...chek em out
but we havent done these sort of things at xul so i m not sure how to do it...sorry:/

we haven't done that too, i understood the first graph but the second one not :/

 

[Soldier313]

yea same here i understood the first one but the second one is kinda complex...not for our level i think:/

 

[iKhaled]

yea same here i understood the first one but the second one is kinda complex...not for our level i think:/

can u have a look at nov/oct 11 u will see a graph where it says draw 2 lines which intersect do u have any i dea how to do that?

 

[Tazyeen K]

can u have a look at nov/oct 11 u will see a graph where it says draw 2 lines which intersect do u have any i dea how to do that?

We did that paper, and well wen u do it, the temp change you get, first increases and then decreases. So when you plot and draw you get One graph that goes up and another that comes down. U then extrapolate it and you get like a upside down V.
Hope u get it.

 

[Soldier313]

ch

can u have a look at nov/oct 11 u will see a graph where it says draw 2 lines which intersect do u have any i dea how to do that?

checked it.....zero idea:S