1. Formation of New Substances:
* Physical Change: No new substances are formed. The molecules themselves remain the same, just their arrangement or state might change.
* Example: Ice melting into water. The molecules of water (H₂O) are still present, just in a different state (solid vs. liquid).
* Chemical Change: New substances with different chemical compositions are formed. This involves the breaking and forming of chemical bonds.
* Example: Burning wood. The wood (cellulose) reacts with oxygen, breaking apart and forming new substances like ash, carbon dioxide, and water vapor.
2. Reversibility:
* Physical Change: Often reversible by changing conditions.
* Example: Freezing water back into ice.
* Chemical Change: Generally irreversible, requiring a different chemical reaction to reverse the change.
* Example: Burning wood cannot be reversed to get back the original wood.
Let me know if you'd like more examples!
