When a solute is added to a solvent, the boiling point of the resulting solution increases, according to the equation , where is the ebullioscopic constant (specific to each solvent), is the molality (moles solute over kilograms solvent), and is the van't Hoff factor, which depends on the extent to which the solute ionizes in solution. A solution boils when the vapor pressure is equal to the atmospheric pressure. When adding a solute to a solvent, the vapor pressure of the resulting solution is lower than the vapor pressure of the original solvent, so it takes a higher temperature for the vapor pressure to equal atmospheric pressure, ultimately resulting in an elevated boiling point. This Demonstration shows the boiling point elevation from solute and solvent data. A graphic approximating the progress of the dissolution process with time is also shown.