- Physical Sciences
electrons that have become removed from the atom and form a âseaâ or region to which the positive atomic kernels are attracted.
mass per unit volume of a substance. The number of molecules in a particular area or a measure...
one reactant loses electrons and another gains electrons
a substance that improves the efficiency of a catalyst is called a promoter.
in a chemical reaction no mass is gained or lost when substances react to form new products....