It's called Chlorophyll, it makes the leaf green and helps with photosynthesis.
Because the leaf is not burning.
It is a chemical change, a degradation of the compounds from the leaf.
Chemical. It has to do with the closing of the part that connects the leaf to the tree and the lack of nutrients causes the leaf to turn colours.
Chemical
chemical
Agent Orange was the toxic, leaf-killing chemical sprayed over Vietnam.
Crushing a leaf is a physical change, not a chemical change because the chemical composition of the leaf remains the same before and after crushing. However, if the crushing process causes the leaf to release certain chemicals due to breaking of cell walls, then it can result in a chemical change.
The change is leaf color is a chemical change.
chlorophyll
oxygen
Mathematics
chorophyll