In this video, Alex will walk through how to calculate the percent composition by mass of each element in calcium carbonate (CaCO₃). This is a key concept for Unit 1 of AP Chemistry, as it helps you understand how to determine the relative amounts of elements in a compound. He will show you step-by-step how to solve the problem, break down the calculations, and explain why this is essential for mastering stoichiometry and chemical formulas. Perfect for AP Chemistry students looking to strengthen their understanding!