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CHEM AND BIO HELP AND TIPS HERE

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holtadit:
An aqueous solution contains barium iodide.

It is possible to obtain a solution that contains Ba2+(aq) but no I–(aq) by adding ……1…… until no
more ……2…… precipitate forms.

Which words correctly complete gaps 1 and 2?
           1                                      2
A) aqueous lead(II) nitrate              white
B) aqueous lead(II) nitrate              yellow
C) dilute sulphuric acid                    white
D) dilute sulphuric acid                    yellow

FROM WINTER 2008 Paper 1
------------------------------------------------------------------------------------------------------------------------------------
I don't understand how the answer could be B. Because if BaI2  reacts with Lead Nitrate u get Lead Iodide (hence the presence of I ions) and u get Barium Nitrate.

Actually in both reactions you would get I ions and Barium ions.

HELP !

nid404:
They want only Ba2+ ions in the solution....which means they want iodide to ppt off....
so to do that, you add lead nitrate...lead iodide precipitates off and the solution contains BaNO3..
Gettin it?

holtadit:
I would just like to take this moment to say...



I LOVE CHEMISTRY !

DEGO:

--- Quote from: Ari Ben Canaan on April 08, 2010, 01:25:08 pm ---Okay for gases use the following:

moles of gas = volume of gas/24000                 NOTE: use 24000 when volume in cm^3 and use 24 instead when volume is in 24 dm^3

For liquids use::

moles of liquid= (volume of liquid in cm^3 * concentration in mol/dm^3) / 1000

For solid use:

moles = mass in grams/mass number of element           NOTE: if its a solid compound then add up the mass nos. of each element

--- End quote ---
Thank You ur the best

DEGO:

--- Quote from: Ari Ben Canaan on April 09, 2010, 07:41:01 am ---An aqueous solution contains barium iodide.

It is possible to obtain a solution that contains Ba2+(aq) but no I–(aq) by adding ……1…… until no
more ……2…… precipitate forms.

Which words correctly complete gaps 1 and 2?
           1                                      2
A) aqueous lead(II) nitrate              white
B) aqueous lead(II) nitrate              yellow
C) dilute sulphuric acid                    white
D) dilute sulphuric acid                    yellow

FROM WINTER 2008 Paper 1
------------------------------------------------------------------------------------------------------------------------------------
I don't understand how the answer could be B. Because if BaI2  reacts with Lead Nitrate u get Lead Iodide (hence the presence of I ions) and u get Barium Nitrate.

Actually in both reactions you would get I ions and Barium ions.

HELP !

--- End quote ---
its B  because its test for anion and cation he is testing for iodine tht form yellow ppt whn (acidified leadnitrate) is added got it?XD

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