Students must answer this question in full. Show all logic, equations, values, units and sig figs. Melamine (C3N3(NH2)3) is a component of many adhesives and resins and is manufactured in a two-step
process from urea (CO(NH2)2) as the sole starting material. How many moles of urea would be required if we
want to collect 1.00 kg of melamine and if the first step in the process is 100% yield, but the second step is only
65% yield?
(1) CO(NH2)2 (1) ► HNCO(1) + NH3(g) (balanced)
(2) HNCO(1) → C3N3(NH2)3 (1) + CO2(g) (unbalanced)

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.