Select which of the following is not a property of gases. Collisions between gas particles are perfectly elastic, meaning that they have the same average energ, before. The size of a gas particle determines the overall volume of the gas. Gas molecules move randomly and rapidly in straight lines. The average kinetic energy is diretly proportaiol to the absolute temperature. Gases are homogeneous mixtures

The statement that **is not a property of gases** is: **"The size of a gas particle determines the overall volume of the gas."** ### Explanation: 1. **Perfectly Elastic Collisions:** - **Property of Gases:** In the kinetic molecular theory, gas particles are assumed to collide perfectly elastically, meaning there is no net loss of kinetic energy during collisions. 2. **Size of Gas Particles:** - **Not a Property of Ideal Gases:** For ideal gases, the size of the gas particles is negligible compared to the volume of the container, meaning the particle size does **not** determine the overall volume of the gas. Instead, the volume is determined by the container and the number of gas particles. 3. **Random and Rapid Movement:** - **Property of Gases:** Gas molecules move randomly and rapidly in straight lines until they collide with another particle or the container walls. 4. **Kinetic Energy and Temperature:** - **Property of Gases:** The average kinetic energy of gas molecules is directly proportional to the absolute temperature of the gas. 5. **Homogeneous Mixtures:** - **Property of Gases:** Gases often form homogeneous mixtures, meaning the composition is uniform throughout. ### Conclusion: While the size of gas particles can influence the behavior of real gases under certain conditions, it does **not** determine the overall volume of an ideal gas, making the second statement incorrect in the context of fundamental gas properties. **Answer:** "The size of a gas particle determines the overall volume of the gas."