A substance has a boiling point of 78 °C. Which of the following is true about the substance?
When the substance is heated, its temperature will start rising above 78 °C after 50% of the liquid has changed to vapors.
When the substance is heated, its temperature will start rising above 78 °C after 100% of the solid has changed to liquid.
When the substance is cooled, its temperature will fall below 78 °C after 100% of the vapor has changed to liquid.
When the substance is cooled, its temperature will fall below 78 °C after 50% of the liquid has changed to solid.