Lesson 4 Pure Substances and Mixtures: We learned how compounds are classified. They can be classified as acidic, basic, or neutral. They can also be classified as organic or inorganic or by their role in the human body. Biochemicals are divided into 4 categories: carbohydrates, lipids, proteins, and nucleic acids. Next we learned that mixtures are a combination of two or more substances that are combined physically but not chemically. Mixtures contain more than one type of substance unlike elements and compounds.
Assignment: Conduct an experiment to test the pH levels of several liquids with litmus paper.