Molecular shapes

Oct 2013
1
0
Hi, guys! Please help me out with my homework. Chemistry is very hard for me, but I'm doing my best in order to understand something. These are some questions that I am not sure about:
1) The "Valence Shell Electron Pair Repulsion" model (VSEPR) is based upon what idea?
a.
Since all electrons have the same charge, the electrostatic force pushes them apart from each other.
b. From simplicity comes complexity.
c. The nuclear force binds electrons to an atom.
d. Atoms do not like to be connected to each other.


I am torn between a and d...

2) The water molecule (good 'ol "H2O") is bent. As a result, which of the following are true? (Note: You may select more than one answer.)

Ice floats.

Ice melts at a higher temperature.

Water is polar.

Water evaporates at a higher temperature.

Microwave ovens can heat food.


The only thing that I know for a fact is that "Microwave ovens can heat food". :)

3) Polar molecules stick together more strongly than non-polar molecules. True or False?

I don't know because I thought that the opposites stick together, but this is not an option... Help? :)
 

Unknown008

CHF Hall of Fame
May 2010
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Mauritius
1) Okay, do you think that atoms do not like to be connected to each other? How do we have so many bonds between atoms then? :)

2) The bent shape doesn't explain why microwave ovens can heat food though! When water is bent, the H atoms get to one side and the O atoms get on the opposite side, thus creating a positive and negative pole, a bit like a magnet.

3) Hint: you can compare how much is the 'stickiness' between two molecules by its intermolecular bonds; aka boiling and melting points.