Asubstance 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.