How many valence electrons does copper contain?

Concerning the 10.0 ml of 0.50 m nacl to 100 ml of solution: when a solution is diluted, does it change the number of moles dissolved?

Aperfume bottle is dropped in the corner of a room. the odor of the perfume can be detected on the other side of the room. which statement best describes this observation?

Identify the lewis acid in this balanced equation: ag+ + 2nh3 -> ag(nh3)2+a. ag+b. nh3c. ag(nh3)2+