Adiel Barnabe João Quinan

*Molecular movements* refer to the various ways molecules move, vibrate, or rotate, depending on their state of matter (solid, liquid, gas) and temperature. These movements are fundamental in understanding physical properties, chemical reactions, and diffusion. Types of Molecular Movements: 1. *Translational Motion* - Molecules move from one place to another in space. - Most noticeable in *gases*. - Example: Gas molecules spreading out in a room. 2. *Rotational Motion* - Molecules rotate around their axes. - Happens in *gases and liquids*. 3. *Vibrational Motion* - Atoms within a molecule oscillate (vibrate) around their equilibrium positions. - Common in *solids, liquids, and gases*, especially at higher temperatures. - Example: Stretching and bending of chemical bonds. 4. *Brownian Motion* - Random movement of particles suspended in a fluid due to collisions with molecules. - Observed under a microscope with tiny particles in water. 5. *Diffusion* - Molecules move from areas of *high concentration to low concentration*. - Driven by molecular kinetic energy. *Temperature effect:* - Higher temperature → faster molecular movement. - Lower temperature → slower movement, molecules vibrate less.

The term *“chemical activity”* refers to the *effective behavior of a substance in a mixture*, taking into account interactions between particles, rather than just its concentration. It’s commonly used in physical chemistry and thermodynamics. Simplified explanation: - In ideal solutions, *activity ≈ concentration*. - In real solutions, due to interactions between molecules or ions, *activity ≠ concentration*. - It represents *the tendency of a substance to react* or participate in a chemical reaction. Basic formula: - *a = γ · c* - a = activity - γ = activity coefficient (depends on the solution) - c = concentration *Example:* - In pure water, the activity of a diluted solute is almost equal to its concentration. - In concentrated solutions or with strong ions (e.g., NaCl), the activity differs from the concentration due to ionic interactions. OKy think about this thema don't forget that you have to search mor ever don't be limited to listen. By😊😊