Give the % composition of all elements in these compounds. (NH4)2 S Molar Mass=

The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a helium atom is (3/2)kbt, at what temperature is the average kinetic energy equal to the bond energy between two helium atoms

Which of the following is in the lanthanide family? a) uranium b) promethium c) silver d) gold

How can liquids be seperated by density a the liquids are absorbed onto a paper b the liquids are turned into seperate vapors c the liquids are collected as they evaporate d the liquids are allowed to seperate into layers