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
I don't this it is A. I thought it might be c.
If temperature is above 0 degree Celsius, water doesn't naturally turn into ice. In fact, the opposite should be expected of.
The only way for water to turn into ice when temperature is above 0 degree Celsius is if there is an external source of energy, or in other words, not naturally occurring.
Therefore this reaction is non-spontaneous.
A non-spontaneous reaction has a delta G greater than 0, which is positive.
Therefore the sign of change in free energy in this case would be positive or A.
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 free energy change (ΔG) in terms of enthalpy change (ΔH) and entropy change (ΔS): ΔG = ΔH - TΔS, where T represents temperature.
In this case, the process is the conversion of liquid water to ice, which involves the release of heat (exothermic process) and a decrease in entropy. At temperatures above 0°C, the change in entropy (ΔS) will be negative, as the transition from a more disordered liquid phase (higher entropy) to a more ordered solid phase (lower entropy) results in a decrease in entropy.
Since ΔS is negative, the sign of the change in free energy (ΔG) will depend on the relationship between enthalpy change (ΔH) and temperature (T). If ΔH is negative and TΔS is positive (TΔS > 0), then the change in free energy (ΔG) will be negative, indicating a spontaneous process. However, if ΔH is negative and TΔS is negative (TΔS < 0), then the change in free energy (ΔG) will be positive, indicating a non-spontaneous process.
In this case, at temperatures above 0°C, the enthalpy change (ΔH) for the conversion of liquid water to ice is negative (as heat is released), and the entropy change (ΔS) is negative (as entropy decreases). Thus, TΔS will be negative (since T is positive), and ΔG = ΔH - TΔS will be positive.
Therefore, the correct answer is A. The sign of the change in free energy for the conversion of liquid water to ice at temperatures above 0°C is positive.