Manny designs an experiment to learn about erosion. First, he sets up three long trays with equal-sized piles of sand at one of each tray. Then he sets up Tray A so that it lays flat on a table. He elevates the end of Tray B that holds the sand by 5 cm. Next, he elevates the end of Tray C that holds the sand in each tray. Finally, he observes and measures how far sand is carried by the way water poured into each tray.

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

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.

What is a difference between a mixture of elements and a mixture of compounds