This quantity equals the negative partial derivative of the grand potential with respect to temperature. Ignoring the indistinguishability of particles leads to a (10[1])non-extensive (10[1])form of this quantity in the Gibbs paradox. Like (10[1])temperature, the Carnot cycle contains two steps in which this quantity is constant. (10[1]-5[2])This quantity was defined as proportional to the natural (10[1])logarithm of the number of microstates (10[1])by (10[1])Ludwig (10[1])Boltzmann. The “arrow of time” is defined because this quantity is non-decreasing for isolated systems by the Second Law of Thermodynamics. For 10 points, name this quantity that is informally the amount of disorder in a system. ■END■ (10[1])