Final answer:
Water transitioning from -10°C to 50°C under a pressure of 760 mmHg will undergo a phase change from solid to liquid, known as melting.
Step-by-step explanation:
If water goes from -10°C to 50°C under constant pressure of 760 mmHg, the phase change that occurs is from solid to liquid. This process is more commonly known as melting, where ice (solid water) converts into liquid water. Based on the phase diagram for water, at a temperature of -10°C and a pressure of 760 mmHg (which is equivalent to about 101.3 kPa, a standard atmospheric pressure), water is in the solid state. As the temperature increases to 0°C, ice begins to melt. The process of melting continues until the temperature reaches the melting point, which is 0°C at atmospheric pressure. As the temperature increases further, the water remains in the liquid phase until it reaches 50°C, well below the boiling point at this pressure.