You have a 155-g sample of Al2O3. If there are 22.5 g of Al in the solution, what is the percent by mass of the solute? Show work.

Schrodinger and heisenberg developed an alternate theory about atomic nature that contradicted some of bohr's model of the atom. how do changes resulting from new technology and evidence affect the reputation of the atomic theory?

Chlorophyll a had the molecular formula c55h72mgn4o5 how many atoms are in this molecule

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.