Which statement is true about energy changes?
a. energy can be created but not destroyed.
b. energy can be created and destroyed.
c. energy can be destroyed but not created.
d. energy cannot be created or destroyed.

D

Explanation:

energy can not be created or destroyed it can only be transferred or changed to one form to another.

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation:

c (diamond),

sio2 (quartz)