A given mass of air has a volume of 6.0 L at 100 kPa. What volume will it occupy at 25kPa?

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.

C. definite shape, definite volume. that is a solid.

It will appear as o2(g) as a reactant 

Answer the molar mass of magnesium is 24.305g/mol.