In: Chemistry
predict the sign of the entropy change of the system for each of the following. justify your answer. a. CO(g) + 2H22(g) = CH3OH (l) b. molten Fe solidifies c. silver bromide precipitates upon mixing AgNO3 (aq) and KBr(aq) d. Zink metal dissolves in hydrochoric acid forming ZnCl2(aq) and H2(g)
Entropy is the sign of randomness/disorderliness in the system. When the system goes from an orderly state to disorderly state, the number of degrees of freedom increases. So enetropy increases. When the system goes from a disorderly state to orderly one entropy decreases.
a. Two gaseous compounds forming one liquid compound. There is a decrease in number of degrees of freedom as gaseous substances are more disorderly than liquids. So the entropy decreases.
b. Molten state is more disorderly relative to solid state, so entropy decreases.
c. AgBr is a solid. Before reaction all the ions dissolved in aqueous medium. Upon AgBr precipitation the number of free ions comes down. So entropy decreases.
d. Solid metal and liquid HCl forms gaseous hydrogen and liquid zinc chloride. Entropy increases as gas has more randomness.