This assignment is related to Geochemistry.
It looks simple, but be careful not to make mistakes.

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Today’s	
 road	
 map:	
 

1.? Thermodynamics	
 of	
 solu4ons	
 and	
 mixtures	
 
1.? par4al	
 molar	
 proper4es	
 
2.? chemical	
 poten4al	
 
3.? ideal	
 mixing;	
 mechanical	
 mixtures	
 
4.? ideal	
 solu4ons	
 
5.? non-­?ideal	
 solu4ons	
 
2.? Phase	
 diagrams	
 (con$nued):	
 
a.? two	
 components	
 
b.? solid	
 solu4on	
 
c.? binary	
 eutec4c	
 
d.? P-­?X	
 diagrams	
 of	
 gases	
 

To
1.?
2.?
3.?
4.?
5.?
6.?

1	
 

Thermodynamics	
 of	
 solu4ons	
 and	
 mixtures:	
 
Most	
 geologic	
 materials	
 are	
 solu4ons	
 of	
 variable	
 composi4on.	
 	
 For	
 example,	
 the	
 
minerals	
 is	
 igneous	
 petrology	
 contain	
 more	
 than	
 one	
 component;	
 they	
 are	
 solid	
 
solu4ons.	
 

 
A	
 solu$on	
 is	
 formed	
 by	
 dissolving	
 one	
 or	
 more	
 substance	
 (solid,	
 liquid	
 or	
 gas),	
 in	
 
another	
 substance	
 (solid,	
 liquid	
 or	
 gas).	
 	
 If	
 a	
 homogeneous	
 solu4on,	
 it	
 can	
 be	
 treated	
 in	
 
thermodynamics	
 as	
 a	
 phase.	
 The	
 solu4on	
 itself	
 can	
 be	
 either	
 	
 
solid	
 (e.g.,	
 plagioclase	
 feldspar	
 is	
 a	
 solu4on	
 of	
 albite	
 (NaAlSi3O8)	
 and	
 anorthite	
 (CaAl2Si2O6),	
 	
 
liquid	
 (e.g.,	
 NaCl	
 or	
 CO2	
 dissolved	
 in	
 water)	
 or	
 	
 
gas	
 (e.g.,	
 our	
 atmosphere).	
 

 
A	
 solu4on	
 may	
 be	
 ideal	
 or	
 non-­?ideal;	
 with	
 thermodynamic	
 proper4es	
 depending	
 on	
 
this	
 ideality.	
 

 
Almost	
 all	
 major	
 igneous	
 minerals	
 (olivine,	
 pyroxenes,	
 amphiboles,	
 feldspars,	
 micas)	
 
are	
 solid	
 solu4ons	
 of	
 two	
 or	
 more	
 components.	
 	
 Quartz	
 is	
 the	
 notable	
 excep4on.	
 

 

 

2	
 

Thermodynamics	
 of	
 solu4ons	
 and	
 mixtures:	
 
Non-­?ideal	
 behavior	
 of	
 a	
 gas	
 mixture	
 is	
 to	
 modify	
 the	
 ideal	
 gas	
 law	
 to	
 ?t	
 available	
 P-­?V-­?T	
 
data.	
 

 

Non-­?ideality	
 in	
 liquid	
 and	
 solid	
 solu$ons	
 can	
 be	
 described	
 as	
 devia4on	
 from	
 ideality	
 à?	
 
using	
 “excess	
 func$ons”	
 

 

 

 

 
To	
 de?ne	
 the	
 composi4on	
 of	
 a	
 solu4on,	
 we	
 need:	
 	
 
1.? to	
 know	
 what	
 substances	
 are	
 present	
 :	
 components	
 or	
 (less	
 restric4vely)	
 
cons$tuents	
 =	
 any	
 combina4on	
 of	
 elements	
 in	
 the	
 system	
 in	
 any