Does the following reaction show an increase or decrease in entropy? N2(g) + 3 H2(g) ---> 2 NH3(g)
A decrease in entropy.
Entropy is associated with the degree of disorder, or number of degrees of freedom. In the reaction
In general, when a reaction has fewer moles of gaseous products than the moles of gaseous reactants, this will be reflected in a decrease in entropy, and vice versa. It's a good job the enthalpy change for this reaction is exothermic, or it would be impossible to make ammonia from nitrogen and hydrogen.