An element is made up of three isotopes, one of which (Bºx has a % abundance of 3.09%, while the other two are unknown. If the mass of the three isotopes are 28X(mass = 27.9769), X(mass = 28.9765) and
30x(mass = 29.9738), and the atomic weight of the element is 28.0855 amu, what are the % abundances of
the other two isotopes?

The small bags of silica gel you often see in a new shoe box are placed there to control humidity. despite its name, silica gel is a solid. it is a chemically inert, highly porous, amorphous form of sio2. because water vapor readily adsorbs onto the surface of silica gel, it acts as a desiccant. despite not knowing mechanistic details of the adsorption of water onto silica gel, from the information provided you should be able to make an educated guess about the thermodynamic characteristics of the process. predict the signs for δg, δh, and δs for the adsorption of water.