Which of the following is a physical change? burning charcoal
lighting a match
cutting vegetables
mixing an acid and a base

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.)

Ted and emily played a mixed doubles tennis match against jack and brenda. in the second match. ted and brenda played against jack and emily. which type of chemical reaction does the situation demonstrate?

This classification of drug typically changes the brain's chemistry and reduces its ability to create its own endorphins.