Lecture 3: Equilibrium Conditions

1. Energy
   1. Entropy
   2. Transforming energy into other potentials
2. Law of mass action
3. Condensation of Al$_2$O$_3$

Practice Problem: Condensation of Corundum from the Solar Nebula

Q1: Calculate the temperature that Corundum (Al$_2$O$_3$) begins condensing from the solar nebula using the following values (assume no other reactions):

$$ \mathrm{2Al + 3O \leftrightarrow Al_2O_3} $$

• Solar abundance (atoms) of Al: 8.51 x 10$^4$
• Solar abundance (atoms) of O: 2.36 x 10$^7$
• Solar abundance (atoms) of H: 2.6 x 10$^{10}$
• Pressure in the nebula: 10$^{-3}$ atm
• Gas constant (R): 8.314 J/mol K
• $\Delta$G$^\circ$ (standard free energy of reaction) for condensation of Al$_2$O$_3$: -1.23 x 10$^6$ J/mol

Q2: At what temperature will this reaction finish condensing all of the Aluminum in the nebula?