ACS Chemistry Practice Exam 2025 – The All-in-One Guide to Exam Success!

Spaghetti sauce is classified as a heterogeneous mixture because it contains various ingredients that can be seen and identified separately, such as tomatoes, herbs, spices, and possibly vegetables or meat. In a heterogeneous mixture, the different components retain their individual properties and are not uniformly distributed throughout the mixture. This means that if you were to take samples from different parts of the sauce, you would likely notice variations in the proportions of ingredients.

In contrast, a homogeneous mixture would appear uniform and consistent throughout, like saltwater, where the salt is completely dissolved and evenly distributed. Similarly, an element consists of only one type of atom, and a compound consists of two or more elements chemically bonded in a fixed proportion, neither of which applies to a spaghetti sauce. The varied composition and the presence of identifiable chunks within the sauce confirm its classification as a heterogeneous mixture.