Which statement describes a reaction at 298 K if AH = 31 kJ/mol, AS = 0.093 kJ/(mol-K)?
A. It is at equilibrium.
B. It is not spontaneous.
C. It is exothermic.
D. Gibbs free energy is negative.

Idon’t understand this page, can someone ?

Asample of the male sex hormone testosterone, c19h28o2, contains 3.88×10^21 atoms of hydrogen.(a) how many atoms of carbon does it contain? (b) how many molecules of testosterone does it contain? (c) how many moles of testosterone does it contain? (d) what is the mass of this sample in grams?

Given sno2 + 2h2 - sn + 2h20 tin oxide reacts with hydrogen to produce tin and water. how many moles of sno2 are needed to produce 500.0 grams of sn?