Question

Estimate the difference between the normal (i.e., at 1 atm) and the standard (i.e., at 1 bar) melting points of ice.

a) 0°C
b) -1°C
c) 1°C
d) -2°C

Answer 1

The difference between the normal and standard melting points of ice is effectively 0°C due to the negligible difference between the pressures of 1 atm and 1 bar.

Step-by-step explanation:

Since the melting point of ice is 0°C at 1.00 atm, as shown in the phase diagrams provided, and considering that standard atmospheric pressure (1 bar) is very close to 1 atm (1 bar = 0.987 atm), we can infer that the difference in melting points would be very small. In fact, the melting point of ice drops with increased pressure, so at the slightly lower pressure of 1 bar compared to 1 atm, ice would melt at a negligibly different or essentially the same temperature. Therefore, we can estimate that the difference would be effectively 0°C.