1. In the substance PbO2, each oxygen has a oxidation number i. e. charge) of -2. What must be the oxidation number (I. e. charge) for the lead atom, Pb, in PBO2?

10-14. (a) when 100.0 ml of weak acid ha were titrated with 0.093 81 m naoh, 27.63 ml were required to reach the equivalence point. find the molarity of ha. (b) what is the formal concentration of a- at the equivalence point? (c) the ph at the equivalence point was 10.99. find pk. for ha. (d) what was the ph when only 19.47 ml of naoh had been added?

An empty fuel tank can still contain and therefore can be even more dangerous than one full of liquid fuel.

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have