One of the main topics covered in Chem 203 lab is how we know the structures of the molecules we study. How do we know that a particular white powdery substance has the molecular formula C9H802? How do we know that a sweet smelling liquid contains an alcohol functional group? How do we know that a waxy substance is a trans fat and not a cis one? These questions are addressed by a set of techniques collectively called spectroscopy and spectrometry. These are techniques by which we can get some structural information about molecules by seeing how they behave in specific circumstances. You're already familiar with UVViz spectroscopy from Chem 150, where we used it to measure the lambda max of colored solutions, mostly of metal ions. In Chem 203 lecture, we'll see briefly how UVViz spectroscopy can be used in organic chemistry, but we won't focus on that technique in the semester's lab. There are three techniques that we will learn about in Chem 203 lab. They are. First, mass spectrometry. This technique allows us to determine a substance's molecular mass and chemical formula by examining how it behaves when ionized and then exposed to a magnetic field. Next, we'll explore infrared or IR spectroscopy, which gives us an idea of the types of bonds and functional groups present in the molecule. Finally, we'll learn about nuclear magnetic resonance or MMR spectroscopy. It's actually the same technique as the MRI imaging used in medicine, although we'll be using it for a somewhat different purpose than doctors do. It's an extremely powerful technique that lets chemists piece together how atoms are bonded to each other and gives us insight into the connectivity, arrangement, and shapes of molecules. These tools collectively enable chemists to determine the structures of molecules and you'll be using them throughout the semester to do just that.