Final answer:
Quantum chemistry is important in understanding the structure, bonding, and reactivity of molecules. It explains why certain molecules exist and how they interact to form compounds. Quantum chemistry is a fundamental part of chemistry that helps predict the energy states and reactions of molecules.
Step-by-step explanation:
Quantum chemistry, also known as quantum mechanics in chemistry, plays a crucial role in understanding the structure, bonding, and reactivity of molecules. It explains why certain molecules exist, the angles of their bonds, and how they interact to form compounds. By applying the principles of quantum mechanics, chemists can predict the energy states and reactions of molecules. For example, quantum chemistry helps explain why water molecules form a bond angle of precisely 104.5° and why water is a liquid at room temperature. While the mathematical calculations involved in quantum chemistry can be complex, the qualitative understanding of these concepts is essential in chemistry.