The hardness of a water sample containing expressed as equivalents (in ppm) is_____________.
(molar mass of is 120.37 g/mol)
Hydrogen peroxide in pure state is:
Hydrogen has three isotopes (A),(B), and (C). If the number of neutron(s) in (A), (B) and (C) respectively, are (x), (y) and (z), the sum of (x),(y) and (z) is :