At temperatures above 0°C, what is the sign of the change in free energy for the conversion of liquid water to ice?

A. Positive
B. Zero
C. Negative
D. Not known

To determine the sign of the change in free energy for the conversion of liquid water to ice at temperatures above 0°C, we need to consider the equation for Gibbs free energy change (∆G) in relation to temperature and the equilibrium constant (K). The equation is as follows:

∆G = -RT ln(K)

In this case, we want to assess the change in free energy for the conversion of liquid water to ice. The equilibrium constant for this reaction is the ratio between the concentrations of products (ice) and reactants (liquid water). As the reaction represents the freezing of water, the concentration of ice will be lower than that of liquid water at temperatures above 0°C.

Since the equilibrium constant (K) will be less than 1, the natural logarithm of a number less than 1 will be negative. This implies that the change in free energy (∆G) will be positive. Therefore, the correct answer is:

A. Positive