Specic heat tells us how heat transfer is related to temperature change for a substance in a given phase of matter (solid, liquid, or gas). At certain temperatures, most substances undergo changes in phasea solid melts into liquid, or a liquid boils and becomes a gas. These phase changes require energy to break the strong bonds between molecules. As we saw in the video, as more heat is transferred into a solid, like ice, its temperature rises until it reaches the melting point. At this point, additional heat transferred goes into melting the solid into a liquid. The amount of heat required to melt a given amount of a solid into a liquid is called the latent heat of fusion. 6-.---.--.-.- 5'5 2 3 H U i E ' I-Ieat added (3 Once melted, additional heat transfer into the liquid raises its temperature until it reaches the boiling point. Again, at the boiling point, additional heat goes into vaporizing the liquid until it has transformed into a gas. The amount of heat required to boil a given amount of a liquid into a gas is called the latent heat of vaporization. Like specic heat, these latent heat values are properties of the particular material. For example, the latent heat of fusion of water is 334 J/g; that is, 334 J of heat must be transferred into 1 gram of solid ice to melt it entirely into liquid water. Similarly, it requires 2,265 J to boil 1 gram of water entirely into a gasthe latent heat of vaporization is 2,265 Jig (or equivalently, 2.27 J/kg). Mathematically, we can describe the amount of heat transfer H into a substance to melt it, when it's at its melting temperature, as H = ml.\" where m is the mass and LI, is the latent heat of fusion. Similarly, the ampunt of heat transfer into a substance to boil it, when it's at its boiling temperature, is H = not\