Friday, November 20, 2009

For Monday:
Read Chapter 8(8.1-8.8) and answer the following questions.

p. 406 # 32, 38,40 42 and 44.  Have these ready to turn in at the beginning of the hour.

If you want to turn oxygen into in to an oxide ion with a negative two charge there would be three steps.

1.  You would need to break the double bond that holds the diatomic oxygen together. That bond energy is given on page 373.

2.  Next you need to add one electron at a time to the gaseous oxygen atom.  The energy released when you add the first electron is called the first electron affinity energy and can be found on p.367 (-141kJ/mol) This reaction is favorable in nature because it is going to lower energy which is exothermic.

3. Next you need to force another electron to an already negative ion.  Remember two negatives repel so you will have to add energy to get them to combine.  This is the second electron affinity energy and is also given on p. 367.  This step is not favorable in nature because you are going to higher energy.  Where will this energy come from??????????

Monday: Go over Born Haber Cycle 

Assignment:Read Sections 8.9-8.10 and answer questions p. 407 #48,50,53,54 and 60 
Tuesday: Lewis Structure
Assignment: Check this web page
https://chemistry.twu.edu/tutorial/VSEPRSum.html
learn all shapes and angles.
Draw the following molecules using the following example
H₂O   AB₂E₂  bent   105^o
ICl₃
TeF₄
XeCl₄
SeF₄
All of the above molecules defy the octet rule, the central atom ends up with more that 8 electrons.