Why does sugar melt?

Answer 1

This is a great chemistry question. I hope you are interested in studying chemistry! First sugar melts at 146 degrees Celsius (or about 295 degrees Fahrenheit). I hope you are really thinking of melting point and not of sugar dissolving into a liquid, like water, or like putting it on your tongue and it "melts" away. This isn't melting, this is dissolving. These are two different things. When something dissolves it really is making a mixture of two substances that is the same throughout the mixture (a homogenous mixture). Sugar dissolves in water to make a homogenous solution. Sugar dissolves on the tongue in saliva (which has a lot of water in it) to make another type of homogenous solution. Melting point is the change of a substance from its solid state to its liquid state. In order to "melt" something enough energy (heat) has to be put into the substance in order for the attraction(s) between different molecules to be overcome. These attractions are called intermolecular forces and there are a few different types of them. The strongest intermolecular force between sugar molecules is known as hydrogen bonding. It is the strongest of all intermolecular forces. So this phenomenon has a tendency to increase a substances' melting point. Another factor is the overall type of solid it is: there generally are 3 types of crystalline solids (sugar is a crystalline solid) - atomic, ionic, and molecular. Atomic solids are things like sodium metal, pure carbon, and things like that. Atomic solids have melting points all over the place. Hydrogen for instance has a melting point of about -269 degrees centigrade (Celsius). Ionic solids are things like table salt, sodium chloride. Ionic solids tend to have higher melting points than other things. Molecular solids, sugar is one, tend to have lower melting points. Of course when we say lower, it is all relative. If you look at a series of similar solids they usually will have a definite trend in melting points within the series. The trend depends on lots of things. Sugar's melting point isn't really all that low, it depends on what you are comparing it to. Compared to something like elemental hydrogen, it is pretty high. Compared to the melting point of something like chromium it is pretty low. Chromium is an atomic solid that melts at 1,857 degrees C. (or about 3,375 degrees F.)

Answer 2

Sugar is composed of crystalline substances such as sucrose, lactose and fructose. If exposed to high temperatures, the molecules rapidly moves around, until the bonds forming the solid are broken, thus it melts.

Answer 3

sugar melts when heated because the force of attraction between the atoms or molecules of sugar become weak and gradually break as more heat is applied to it and soon the sugar melts to become liquid.

Answer 4

Sugar, or sucrose, is an organic molecule and has covalent bonding. Salt has ionic bonds. Covalent bonds are easier to separate when adding energy to them than ionic bonds are, which translates to lower melting and boiling points.