## Pumpkin890 2 years ago Which describes the temperature changes that would be observed as ice at −15 degrees Celsius is changed to water at zero degrees Celsius? Answer steady increase in temperature from −15°C to 0°C with gradual change from ice to water gradual increase in temperature of ice from −15°C to 0°C, holding at 0°C as ice melts to water steady decrease in temperature from water at 0°C to ice at −15°C holding at −15°C as ice melts to liquid water and then gradual warming of water to 0°C Any help would be appreciated. I am confused because the freezing point is at 0 degrees Celsius?

1. aaronq

"gradual increase in temperature of ice from −15°C to 0°C, holding at 0°C as ice melts to water" is correct. |dw:1375113066962:dw|

2. cmerz

Just as a hidden note is passed in class without being detected by the teacher, the heat released as a liquid that changes to a solid is not detected by a thermometer. To understand why, think about what happens on the particle level when a sample of frozen water at zero degrees Celsius changes to liquid water at zero degrees Celsius. You know you have to add heat to a substance to melt it. A certain amount of heat must be added to disrupt many of the attractive intermolecular forces holding the molecules together in the ordered solid. The liquid particles at zero degrees Celsius still have the same average kinetic energy, but they now have greater freedom of movement and are moving over greater distances. A substance’s latent heat ("hidden heat") is the amount of heat required to change the phase of a given mass of the substance. Point B is where this is represented The believe this would mean a steady increase in temperature with a hold at 0ºC for the ice to melt to water