Calculation of Change in Entropy
To calculate the change in entropy, we need to use the formula ΔS = Q/T, where ΔS is the change in entropy, Q is the heat transferred, and T is the temperature at which the heat transfer occurs.

Calculation of Heat Transferred
First, we need to calculate the heat transferred from the ice to convert it into water. The heat required to convert 1 gram of ice at 0°C to water at the same temperature is called the latent heat of fusion.

Calculation of Latent Heat of Fusion
The latent heat of fusion (L) of ice is 80 cal/gram. Therefore, the heat required to convert 0.0273 kg (27.3 grams) of ice to water will be:

Q = mL = (27.3 g) × (80 cal/g) = 2184 cal

Calculation of Temperature
Since the ice and water are at the same temperature (0°C), the temperature (T) at which the heat transfer occurs is also 0°C.

Calculation of Change in Entropy
Now we can calculate the change in entropy using the formula:

ΔS = Q/T = 2184 cal / 273 K = 8.01 cal/K

Therefore, the change in entropy when 0.0273 kg of ice at 0°C converts into water at the same temperature is 8.01 cal/K.

Explanation
The change in entropy occurs due to the transfer of heat from the ice to convert it into water. The entropy of the ice decreases as the ice molecules become more ordered during the conversion to water molecules. At the same time, the entropy of the water increases due to the increase in the number of possible arrangements of water molecules. The net change in entropy is the difference between the decrease in entropy of the ice and the increase in entropy of the water.

0.273 kg