Unformatted text preview: — C — H Methyl propane (melting point = -11.7 degree Celsius) II. Ionic Compounds.
1. It is a different model for bonds
2. a. 23NA _”1e— + 22NA (costs energy)
b. 35C1 + le- ">360 (releases energy)
0. Taking an electron from sodium and throwing it at chlorine results in net loss of energy.
3. Ions interact equivalently with all the ﬁrst nearest neighbors.
4. Balls of charge, both positive and negative are joined together by columbic attractions. _
5. N0 molecules exist, no molecular formula. Only the empirical formula is relevant. III. Metals:
A. They are alloys (mixtures of multiple atoms) 1. They like to lose electrons.
2'. Metal _p Metal n+ +ne~ IV. Network solids:
A. Electrons are shared via directional bonds but bonding goes on and on and on.
For example: different versions of carbon such as diamond, graphite and nanotube.
1. So empirical formula is not enough. We need structural formula too.
2. Hence we need to calculate % composition by mass.
B. Consider C2H60
1. For 1 mole of C2H5O we require
a. C =12.011 g/ mole
Since the compound has 2 moles of C that means it has 24.022 grams of C
(2* 12.01 1)
b. H = 1.0079 gm/ mole
Compound has 6 moles of H; therefore it has 6.047 grams of H ...
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- Fall '07