Ilearning about chemical or physical properties and i don't understand whether mercury that has a density of 13 g/ml is chemical or physical or how to determine how to determine the difference

Density is a physical property of mercury. Chemical properties are used to describe how a certain element or compound interact with other combounds. Whereas physical properties focus solely on how the element or compound behave under different conditions (boiling point, melting point, thermal conductivity, density, hardness, etc.)

This scenario is called diffusion. particles are moving from regions of high concentration to low concentration.