Respuesta :
In chemical changes new substances are formed and the process is often difficult to reverse. During chemical changes particles do change with atoms or ions regrouping. Bonds between atoms break and new ones form and energy is either given out or taken in. Some chemical changes are initiated by mixing
Most of the sand is made up of loose grains and tiny pieces of worn out and disintegrated rocks. This physical break down of different rocks is termed as weathering.
A physical change happens when the physical form of a substance is altered but it does not transform it into another substance.
Therefore, the formation of sand is only a physical change, and not chemical, because weathering only changes the size of loose fragments of rock that make up the sand.