Chemistry: Post your doubts here!

[Bba321]

Hi
Can anyone tell me if we write 4s and then 3d in group 4 elements like Ge,Sn and Pb or do we write 3d or the other way?

Confused please help
Thanks

 

[Fatima Naeem]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_12.pdf

Can someone please solve question 10? I don't get why it is B. :/

 

[3l_general]

October 2012 , paper 13 .
Question 5
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/

 

[Snowysangel]

Could someone please explain the reaction between iodine and thiosulfate ions to me?

 

[princess Anu]

Q29

 

[Paris Palmer]

HCl is a polar molecules. H has a partial positive charge while Cl has a partial negative charge since chlorine is highly electronegative compared to hydrogen. The force between HCl molecules is permanent dipole attraction. Not induced dipole forces.

Why is the Ionic Radius of transition elements invariant?

 

[muhammad dabeer]

hi guys,
i want a lvl chem past papers of 1996 if any1 have it plz upload it soon.
according to my knowledge kgs library contains it.

 

[Paris Palmer]

hi guys,
i want a lvl chem past papers of 1996 if any1 have it plz upload it soon.
according to my knowledge kgs library contains it.

Can someone please send me a link to download Chem A Levels pastpapers of June 2014?

 

[Maqb0ol]

Can someone please send me a link to download Chem A Levels pastpapers of June 2014?

Here it is "http://maxpapers.com/category/qualifications/international/cambridge/a-level/a-level-chemistry-9701/"

 

[princess Anu]

Solution please?!

 

[Awesome12]

How is it C??

 

[princess Anu]

How is it C??

View attachment 49720

The ratio of volume of gases is the ratio of their moles
So 1:3:1:1:1 is the ratio shown by the equation but the ratio given is 1:6
therefore 30cm of O2 will be used leaving the excess (30cm)
and we get 10 cm of CO2, h20 nd SO2 makes a total of 6o. But since the mixture is cooled, h20 will convert into water and so the remaining volume will be 50.

 

[Awesome12]

The ratio of volume of gases is the ratio of their moles
So 1:3:1:1:1 is the ratio shown by the equation but the ratio given is 1:6
therefore 30cm of O2 will be used leaving the excess (30cm)
and we get 10 cm of CO2, h20 nd SO2 makes a total of 6o. But since the mixture is cooled, h20 will convert into water and so the remaining volume will be 50.

Thanks.

 

[Awesome12]

Why is it B?

 

[princess Anu]

Why is it B?

View attachment 49733

The dipoles in A C D cancel out but not in B.
Remember, Trigonal planar shaped molecules can cancel dipoles if all the bonds made are polar, like in C.

 

[Awesome12]

The dipoles in A B D cancel out but not in C.
Remember, Trigonal planar shaped molecules can cancel dipoles if all the bonds made are polar, like in C.

But the answer is B. And both B and C are trigonal planar shaped molecules.

 

[princess Anu]

But the answer is B. And both B and C are trigonal planar shaped molecules.

Like I said, IF ALL THE BONDS ARE POLAR. Therefore C has no dipoles while B has.
Sorry, I mistyped. It's 'The dipoles in A C D cancel out but not in B'.

 

[slisjunknown]

I do not understand the periodic trends in period 3 for electrical conductivity, boiling points, ionic radii and atomic radii. many sources show different graph representation. It would be highly appreciated if anyone can explain the graphs for the properties. Is there any specific way to place values in the graphs? Cuz my teacher says you have to guess the values...

 

[savera]

I do not understand the periodic trends in period 3 for electrical conductivity, boiling points, ionic radii and atomic radii. many sources show different graph representation. It would be highly appreciated if anyone can explain the graphs for the properties. Is there any specific way to place values in the graphs? Cuz my teacher says you have to guess the values...

I hope this helps. If not don't hesitate to ask questions

 

[slisjunknown]

I hope this helps. If not don't hesitate to ask questions View attachment 49764 View attachment 49765 View attachment 49766 View attachment 49767

Thnks a lot..these notes are much simpler. Where r u from?