Covalent structure (2) Shapes & polarity questions

Assignment: Questions on Topic 4.3: Shapes & polarity

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Note that the last two questions are for only.

Predict the shape and bond angles of:

i. boron trichloride, BCl3

2 lines

ii. phosphoryl chloride, POCl3

2 lines

iii. phosphine, PH3

2 lines

iv. hydrogen cyanide, HCN

1 line

 

 

Explain why sulfur dioxide molecules, SO2, have a bent shape whereas carbon dioxide molecules, CO2, are linear

5 lines

 

 

Explain why C=O bonds are polar and yet the carbon dioxide molecule is non-polar.

2 lines

 

 

Explain why the H-N-H angle in ammonia is smaller than the H-N-H angle in the ammonium ion.

5 lines

 

 

A simplified model of benzene, C6H6, shows the six carbon atoms in a ring with alternate single and double bonds between the carbon atoms. Each carbon atom is also bonded to one hydrogen atom.

i. Based on the model described above predict the bond angle in benzene.

2 lines

ii. In cyclohexane, C6H12 the six carbon atoms are also in a ring but are joined to each other only by single bonds. Each carbon atom is also bonded to two hydrogen atoms. Predict the bond angle in cyclohexane.

2 lines

 

 

Fluorine and oxygen are very electronegative elements. Explain why hydrogen fluoride, HF, and water, H2O, are very polar molecules but tetrafluoromethane, CF4, and carbon dioxide, CO2 are non- polar.

5 lines

 

 

cheeky only

Predict the shape of:

i. xenon tetrafluoride, XeF4

2 lines

ii. the iodine tetrachloride ion, ICl4

2 lines


iii. chlorine trifluoride, ClF3

3 lines

 

 

 

cheeky only

Predict all the bond angles in:

i. phosphorus pentafluoride, PF5

2 lines

ii. the phosphorus hexafluoride ion, PF6

2 lines

 

 


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