Final answer:
The chemical reaction described is the tarnishing of silver, where silver reacts with sulfur to form silver sulfide, an exothermic reaction indicated by the release of heat and the characteristic black tarnish formed on the silver surface.
Step-by-step explanation:
The question refers to a chemical reaction where silver metal reacts with sulfur to form silver sulfide, known as tarnish. This tarnish turns the silver surface dark and streaky black. The warmth mentioned is indicative of an exothermic reaction, where heat is evolved. Unlike silver's reaction with oxygen, which typically does not lead to silver dissolving, silver reacting with sulfur forms a solid compound, not a dissolution.
The physical senses such as a change in temperature, color change, or the formation of new substances, like the noticing of heat or the silver turning black, are key in identifying this chemical change.
As an example of a similar reaction with oxygen, we can reference the combustion of magnesium. When magnesium reacts with oxygen, it produces a bright white flame, and the magnesium is transformed into a crumbly white powder known as magnesium oxide (MgO). However, it is important to note that silver's reaction with oxygen differs as silver does not readily react with oxygen at room temperature to form silver oxide.