Imagine that we have a fake garnet-clinopyroxene Fe-Mg exchange thermometer. This is actually a real geothermometer, but all of the numbers have been changed. The reaction for this fake thermometer is: Mg2AlSiO2 + CaFeSiO = Fe2Al2Si3O12 + CaMgzSiO6 (Mg-rich garnet + Fe-rich cpx = Fe-rich garnet + Mg-rich cpx). Experimental work has produced data on an InK vs. 1/T plot (see below) that yields a line defined as:
y = -2347x + 0.5726
Assume that the ΔV for the reaction is 2.983 J/MPa, assume that the experiments were run at 0.210 GPa, and assume ideal solution models.
With this information:
1. Calculate the ΔS for the reaction.
2. Calculate the ΔH for the reaction.
3. Determine what Kp is equal to in terms of variables (not numbers, since you don't have those).
4. Derive the equation for TC in terms of P and InKp (basically derive equation 27.36 for this fake reaction given the above variables). Please show all of your calculations, specifically showing how you have solved for each requested variable. (40 pts)
800
TC
700
600
550
-1.8
y = -2347x + 0.5726
-1.6
InK -1.4
-1.2
-1.0 0.00090 0.00095 0.00100 0.00105 0.00110 0.00115 0.00120 1/T(K)