Final answer:
The dispersal of sugar molecules throughout the coffee after adding cream and sugar is known as dissolution, resulting in a homogeneous solution. This occurs as the sugar interacts with and is evenly distributed within the hot coffee, making it sweet.
Step-by-step explanation:
When cream and a teaspoon of sugar are added to a cup of coffee and the sugar molecules disperse throughout the hot coffee, the process that occurs is called dissolution. This is evident when the solid sugar dissolves in the coffee, resulting in a homogeneous mixture known as a solution. The hot coffee acts as the solvent and the sugar as the solute. In a solution, the solute particles are dispersed evenly throughout the solvent, making the coffee sweet uniformly.
As the sugar dissolves, no visible traces of sugar are left due to the molecular interaction between the sugar and the water molecules in the coffee. The dissolution process is driven by the motion of the solvent molecules and the tendency of solute and solvent to mix and achieve a more evenly distributed energy state.