Final answer:
The ice melts at a temperature of 0°C, which is the melting point where the solid and liquid phases of water coexist.
Step-by-step explanation:
The temperature at which the ice melts in a sealed container is 0°C. During the phase transition from ice to liquid water, the temperature remains constant at 0°C, even as heat is absorbed by the ice. This critical point is known as the melting point, and it signifies where the solid phase (ice) and the liquid phase (water) coexist. Once all the ice has melted, the water temperature can start to rise as additional heat is applied until it reaches the boiling point where it becomes water vapor.