An unknown radioactive substance has a half-life of 3.20 hours . if 22.8 g of the substance is currently present, what mass a0 was present 8.00 hours ago? express your answer with the appropriate units.

Which statements are true about electrolysis? check all that apply. electrolysis requires an acid be present. electrolysis is described by two half-reactions. electrolysis is not an industrial process. electrolysis results in commercially valuable products. electrolysis involves the transfer of electrons. reduction results in the loss of electrons. oxidation results in the loss of electrons.

In the following table, all the columns for the element calcium are filled out correctly. element electron structure of atom electron structure of ion net ionic charge calcium 1s22s22p63s23p64s2 1s32s22p63s23p64s1 +1 true false

How many grams of ammonia are produced when 1.0 mole of nitrogen reacts