6. A compound has chemical and physical properties which are a. Identical to
b. Different than one, but the same as the other of
Different than cither of
d. Unknown
C.
7. A chemical change can only be undone by:
a. A chemical reaction
b. A nuclear reaction
A phase change
d. They can't be undone

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.)

What is the polyatamic ion of borate

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?