Final answer:
When ethanol transitions from a liquid to a gas, intermolecular hydrogen bonds are broken, not the covalent bonds within the ethanol molecule.
Step-by-step explanation:
Phase Change from Liquid to Gas in Ethanol
When ethanol (CH₃CH₂OH) changes phase from the liquid to the gas, the bonds or forces being broken are the intermolecular forces, specifically hydrogen bonds.
Ethanol molecules in the liquid phase are attracted to each other by these hydrogen bonds, which occur between the hydrogen atom of one ethanol molecule and the oxygen atom of a neighboring ethanol molecule. As energy in the form of heat is added, these bonds are disrupted, allowing ethanol molecules to move more freely and transition into the gas phase.
It's important to note that covalent bonds within the ethanol molecule itself, such as the C-H and O-H bonds, are not broken during this phase transition. Instead, phase changes involve the breaking and forming of intermolecular forces that hold molecules together in a liquid or solid state.