While doing a scinece project with my daughter we attempted to melt two sugar cubes. We poured alcohol on one sugar cube and vinegar on the other. The sugar cube with the alcohol melted at a faster speed. Why was this?
The reason the sugar cube melted faster when you poured alcohol on it instead of vinegar is because of the different chemical properties of these substances.
To understand why this happened, we need to know that sugar is a type of carbohydrate called sucrose, which is composed of glucose and fructose molecules bonded together. When sugar dissolves or melts, these bonding forces between the sugar molecules are broken, allowing them to separate and spread out.
Alcohol, such as rubbing alcohol or isopropyl alcohol, is a solvent known for its ability to dissolve many substances, including sugar. It has a molecular structure that allows it to interact with the sugar molecules by forming hydrogen bonds, which weakens the intermolecular forces holding the sugar molecules together. As a result, the sugar molecules are able to separate more easily and dissolve in the alcohol, causing the sugar cube to melt faster.
On the other hand, vinegar is a weak acid composed mostly of water and acetic acid. While it can also dissolve sugar, it does so at a slower rate compared to alcohol. Acetic acid in vinegar can form weak hydrogen bonds with the sugar molecules, but these bonds are not as strong as those formed by alcohol. Therefore, the intermolecular forces in vinegar are not as effective in breaking the sugar molecules apart, causing the sugar cube to dissolve more slowly.
So, the difference in the melting speed of the sugar cubes when exposed to alcohol and vinegar is due to the varying abilities of these substances to weaken the intermolecular forces holding the sugar molecules together.