Bond angles in Chemistry?

[Zenzenzen]

I was wondering what would be the appropriate way to write bond angles in chem paper 2.

For example, say you have to find the H-C-H bond angle in CH2=C=O.
I would write 120 degrees. However, the mark scheme gives a range of 117-120. Do I have to state the range in my answer or does that just mean my answer has to be in that range?

All help appreciated!

 

[Anonymousx3]

Your answer just has to be in that particular range.
Writing 120 degrees is perfectly fine.

 

[Zenzenzen]

Alright thanks!

 

[filza94]

and can we rite 117 degree also???

 

[zarajay]

one more thing guys..
why is C-Cl bond the weakest when compared to C-H and C-F
...for C-F what i thnk is bcz F is more electronegative, it attracts the bonded pair towards itself n so more strength of the bond, is it right?...but why C-Cl is bein chosen over C-H?? ! :S

 

[Feelguud77]

Cl atom is larger than C and F, as a result C-Cl bond length is greater, therefore bond enthalpy is less..........yeah, thats about it

 

[zarajay]

Cl atom is larger than C and F, as a result C-Cl bond length is greater, therefore bond enthalpy is less..........yeah, thats about it

hell yeah thats it! :O
i wonder why this thing never hit me before! =.=
anywayss thankss alot! =)

 

[Feelguud77]

No prob dude BJ

 

[killer22]

I was wondering what would be the appropriate way to write bond angles in chem paper 2.

For example, say you have to find the H-C-H bond angle in CH2=C=O.
I would write 120 degrees. However, the mark scheme gives a range of 117-120. Do I have to state the range in my answer or does that just mean my answer has to be in that range?

All help appreciated!

How do you find the 120 degrees in the first place? I simply don't know how to do questions like these! :/

 

[killer22]

Anyone?