Explanation:
Since, it is shown that the reaction has been reversed. Therefore, value of
will become
.
Hence, new 
= 
= 20
Also, the number of moles of each reactant has been halved. So,
for the reaction
will also get halved.
Therefore,
=
= 
= 4.47
As the value of
is given as +39.0 kJ. So, it means that the reaction is endothermic in nature. So, energy of reactants will be more than the products. Hence, according to Le Chatelier's principle reaction will move in the forward direction.
As a result,
will also increase with increase in temperature.
A hydrate is a substance where in it contains water and other constituent elements. To know whether if that compound was a hydrate,you should record its mass, then put it in a test tube and heat it with a Bunsen burner. If the compound is a hydrate, the water in the compound will discharge in the form of water vapor. At the next 5-10 minutes, remove it in the test tube and weigh it up again. If the mass is now fewer, that means that there was water existing that has now evaporated, and the compound was a hydrate.
The geosphere is about 99.94% of Earth's mass, so C is the answer.