The diffusion of a gas is faster than that of a liquid at the same temperature because of the differences in intermolecular forces and the relative kinetic energies of the particles. Both gases and liquids have particles with kinetic energy related to temperature, but the nature of the particles and the forces between them differ significantly.

In a gas, the particles are widely separated and the intermolecular forces are very weak (essentially negligible). This allows the particles to move freely and independently, with minimal resistance to their motion. The kinetic energy of the gas particles is therefore almost entirely converted into translational motion, resulting in rapid diffusion.

In a liquid, the particles are much closer together and experience stronger intermolecular forces (e.g., van der Waals forces, hydrogen bonding). These forces impede the movement of the particles, requiring more energy to overcome them. While the kinetic energy of the liquid particles is the same as that of the gas particles at the same temperature, a greater proportion of that energy is used to overcome intermolecular forces rather than to contribute to translational motion. This results in a slower rate of diffusion compared to a gas.

Therefore, the weaker intermolecular forces and greater freedom of movement in gases allow for faster diffusion compared to liquids, even at the same temperature.

Describe: Diffusion is the net movement of particles from a region of high concentration to a region of low concentration. The rate of diffusion is how quickly this movement occurs. Relative molecular mass (Mr) is the mass of a molecule compared to the mass of a hydrogen molecule (H₂). A gas with a higher Mr will have molecules that are, on average, heavier than those of a gas with a lower Mr. This means the heavier molecules have lower average speeds at a given temperature.

Explain: The rate of diffusion is directly proportional to the average speed of the gas molecules. This relationship is explained by the kinetic molecular theory. The kinetic molecular theory states that gas particles are in constant random motion and that the average kinetic energy of the particles is proportional to the absolute temperature of the gas. The average kinetic energy is also directly proportional to the mass of the particle. Therefore, heavier molecules have lower average speeds. This results in a slower rate of diffusion. A gas with a lower Mr will have molecules with higher average speeds, leading to a faster rate of diffusion. The faster the molecules move, the more rapidly they spread out and mix.

In summary: Higher Mr = lower average speed = slower diffusion rate. Lower Mr = higher average speed = faster diffusion rate.

Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration. This movement occurs randomly and is driven by the kinetic energy of the particles. Kinetic particle theory states that all matter is in constant random motion. The kinetic energy of these particles is directly proportional to the temperature of the substance.

In diffusion, particles are constantly moving and colliding with each other. The higher the temperature, the greater the average kinetic energy of the particles. This means they move faster and collide more frequently. This increased frequency of collisions leads to a faster rate of diffusion.

Particle size also affects the rate of diffusion. Smaller particles diffuse faster than larger particles because they have a greater surface area to volume ratio. This means that a smaller proportion of the particle's kinetic energy is 'wasted' on internal collisions, and more of it contributes to movement across the concentration gradient. Therefore, smaller particles diffuse more rapidly.

Temperature's effect on diffusion rate:

• Higher temperature: Increased kinetic energy, faster particle movement, faster diffusion.
• Lower temperature: Decreased kinetic energy, slower particle movement, slower diffusion.