A Level Chemistry OCR Practice Exam

What does the term mechanism refer to in chemistry?

1. A method of balancing chemical equations

2. A series of steps showing the path of electrons in a reaction

3. The final state of products in a reaction

4. The theoretical yield of a chemical reaction

The correct answer is: A series of steps showing the path of electrons in a reaction

The term mechanism in chemistry specifically refers to a series of steps that detail how reactants transform into products during a chemical reaction, highlighting the path taken by electrons. This often includes which bonds are broken and formed, as well as the intermediates that may be created along the way. Understanding a reaction's mechanism allows chemists to grasp the underlying processes, predict reaction outcomes, and design experiments or syntheses effectively. While balancing equations, arriving at product states, and calculating theoretical yields are all important aspects of understanding chemical reactions, they do not capture the detailed, step-by-step pathway of the electron movement and the changes at the molecular level that are integral to the concept of a reaction mechanism.