gen chem questions

[suhshi]

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from ACS

the fact that Pt(NH2)2Cl2 exists in two different isomeric forms offer evidence that the geometry is:

answer is square planar




and


why are the bonds in ethene shorter than a benzene ring if they both contain double bonds.



thanks for your help

 

[sixkiller]

from ACS

the fact that Pt(NH2)2Cl2 exists in two different isomeric forms offer evidence that the geometry is:

answer is square planar




and


why are the bonds in ethene shorter than a benzene ring if they both contain double bonds.



thanks for your help

Draw the square planar conformation....

It's shaped like an X....now place the substituents in any order you choose. You will see that either a cis or trans isomer also exists.

The second question is most easily understood by applying the concept of resonance. Because the pi electrons are delocalized...each double bond has "less" double bond character than that of ethene where the pi electron is localized to a greater extent.

 

[suhshi]

thanks for your help

in addition


why would the bonds between SiO2 be closest to 110
when Kaplan says that CO2 is 180 degrees apart, and dont Si and C both have sp hybridization because they both have 4 valence electrons

 

[dl9006]

i think SiO2 is a network polymer.

instead of double bonding with the oxygens, it forms chains to other sio2 molecules.

Thus you get more of tetrahedral shape.

 

[sixkiller]

thanks for your help

in addition


why would the bonds between SiO2 be closest to 110
when Kaplan says that CO2 is 180 degrees apart, and dont Si and C both have sp hybridization because they both have 4 valence electrons

Requires a bit of extra knowledge....silicon dioxide is usually interpreted as quartz/silica...ect

It's tetrahedral.
http://en.wikipedia.org/wiki/Quartz

 

[suhshi]

thanks much. i get it