it may be a catalyst, a spectator ion a solvent.
These substances are called catalysts.
Soaking is not a chemical change, unless contact with water results in a chemical reaction - such as adding sodium to water.
Physically or chemically.
Ash and smoke.
reaction
Argon is chemically inert and does not have any reaction under normal conditions.
Mass is a basic properties of the body. The mass of a body does not change with a physical reaction, such as expansion. Neither does its weight. The only change is probably just its volume. The mass of the body will change under a nuclear reaction or chemical reaction, because the body has changed into a different entity -- it becomes a different object or objects. Its nature has changed. ==========================
Dalton
A chemical reaction
It is possible but this reaction was not studied.
starches
The catalyst is not a reactant; a catalyst only favors a chemical reaction, the reaction rate and yield.