What is the difference between a mixture, a solution, and a pure substance?

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.)

Areaction is first order with respect to reactant x and second order with respect to reactant y. which statement describes the rate law for this reaction?

What is the correct lewis dot structure for arsenic?