For the chemical reaction c2h6 + 137 kj c2h4 + h2, the chemical energy of the
a. reactant is greater than the chemical energy of the products.
b. products is greater than the chemical energy of the reactant.
c. reactant and the chemical energy of the products are equal.
d. reaction is conserved.

The reaction C₂H₆+137kJ→C₂H₄+H₂ is endothermic since the energy is being absorbed by the reaction and not released.  We know this by the fact that the energy is on the reactants side of the reaction.  If the energy was on the products side of the reaction we would call it exothermic since energy would be being released.  Since this reaction is endothermic we know that the products will have more energy than the reactants which means that the answer is B.

(the equation in the question does not have an arrow in it so I assumed it was between the 137kJ and C₂H₄).

I hope this helps.  Let me know if anything is unclear.

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water