A sample of ethanol, 20 g of which is solid and 20 g being liquid is at -114◦C, which is the freezing point of ethanol.
Identify the statement that describes what initially happens when the sample is placed in a container at -200◦C and the heat flows out of the sample.
A. The liquid part freezes while the temperature of the sample decreases
B. The liquid part freezes while the whole sample remains at the same temperature.
C. The solid part melts while the whole sample remains at the same temperature.
D. The liquid part freezes while the temperature of the sample increases
E. Both the solid and liquid parts maintain their phases while the temperature decreases.
Thermodynamic values for water:
Tf = 0°C
Tb = 100°C
CH2O(s) = 2.09 J/g-K
CH2O(l) = 4.184 J/g-K
CH2O(g) = 2.03 J/g-K
ΔHvap = 2260 J/g
ΔHfus = 334 J/g
Kb = 0.512° C/m
Kf = 1.86° C/m
R = 8.314 J/mol-K = 0.08206 L-atm/mol-K