Select the correct answer.
A compound has an empirical formula of C2H5 What is true about this empirical formula?
A. it models the structure of the compound.
B. It shows the ratio of elements in the compound.
C. it gives the mass of each atom in the compound.
D. It indicates the number of atoms in the compound

E. it describes only this one compound

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.