An iron ore (Fe3O4) was analyzed by dissolving a 1.1324 g sample in concentrated HCl. The resulting solution was diluted with water, and the iron(III) was precipitated as the hydrous oxide Fe2O3.xH2O by addition of NH3. After filtration and washing, the residue was ignited at high temperature to give 0.5394 g pure Fe2O3 (MW 159.69 g/mol). Calculate (a) the % Fe (MW 55.847 g/mol) and (b) % Fe3O4 (MW 231.54 g/mol) in the sample.

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".

it is a solid

explanation: