Which indicator of a chemical reaction is shown in the picture?
a. the formation of a gas
b. the formation of a precipitate
c. a change in energy

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

May someone me with these science questions

Displacement is the slope of a velocity vs. time graph a. true b. false