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1/28/02, 1/29/02 Regular Chemistry Homework

Read pages 255-265 in Chapter 8 of your book.

Answer the following questions pertaining to that material:

 

1) Referring to figure 8-2, you might conclude that an ammonia molecule has a T-shape.  Is this correct?

 

 

2) What are ball and stick models used for?  What does the ball represent in these models?  The sticks?

 

 

3) What is a linear shape?  What is a triangular shape? What are pyramidal shapes? Are all these shapes symmetrical?  What does it mean to be symmetrical?

 

 

 

4) What is the VESPR theory?  What does the VESPR theory state? Is this theory always applied in chemical situations?

 

 

 

5) Explain linear molecules, their bond angles and give some examples.

 

 

 

 

6) What is trigonal planar shaped molecule? Give some examples, and what are their bond angles?

 

 

 

 

7) What is a tetrahedral shaped molecule? Give some examples, and what are their bond angles? (More than one)

8) What are pyramidal shaped molecules?  Give some examples, and what are their typical bond angles?  Why do molecules take this shape?

 

 

 

 

 

9) What is a bent molecule?  What molecule represents a bent molecule? What is the bond angle of this molecule?  What causes the “bentness” of this molecule? Why is this molecule shape’s so significant?

 

 

 

 

10) What are hybrid orbitals?  Draw the following:

            sp

 

 

 

 

            sp2

 

 

 

 

                sp2

 

 

 

 

11) What kind of hybrid orbitals are in a molecule of boron trichloride? Methane? Water?

 

 

 

 

12) What two important trends in bond length you should be aware of?

 

 

 

 

13) Many fruits produce ethane, which helps them ripen.  The molecular formula for ethane is C2H4, and the 2 carbon atoms are joined by a double bond.  Draw a structural formula and a ball-and-stick model for ethane.  Identify the hybrid orbitals on each carbon atom and estimate the bond angles.