A hot coffee with sugar dissolved in it is classified as a homogeneous mixture (solution) because the sugar particles are evenly distributed throughout the coffee. In a homogeneous mixture, the components are so finely mixed that they cannot be distinguished from one another, resulting in a uniform composition. This is different from a heterogeneous mixture, where the components remain separate and can be identified, and a colloid, where the particles are larger than those in a solution but still do not settle out. In this case, the sugar completely dissolves in the hot coffee, making it a solution.