Two atoms of a single element that differ in number of neutrons are said to represent two distinct of that element.

The drawing represents the movement of particles in a substance. what changes of state can this substance undergo

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.

The rate constant for the reaction below is 6.2 x 10−5 mol l−1 s −1. if the initial concentration of a is 0.0500 m, what is its concentration after 115 s?