With revision of 6 questions and 20 points! last ones.

in the reaction, c (s) + o2 (g) arrow co2 (g), the reducing agent is:
the c
the o2
the co2 (my answer)
the c and the o2

preventing iron corrosion is important because many structures, including bridges and iron railings, are likely to rust over time and become weaker. which of the following conditions would make corrosion more likely?
increasing the moisture level near the structure (my answer)
reducing the concentration of electrolytes in solutions in contact with the structure
neutralizing any acidic solutions near the iron
painting the iron surface

when balancing the oxidation and reduction half-reactions for acidic solutions, you should:
use h+ and oh− equally in order to balance the equation
use h+ only in order to balance the equation
use h+ and h2o, as needed to balance the equation (my answer)
use oh− and h2o, as needed to balance the equation

in the reaction, zn (s) + fe+2 (aq) arrow zn+2 (aq) + fe (s), the oxidizing agent is:
the zn
the fe
the zn+2 (my answer)
the fe+2

which balanced equation shows the result of balancing the following two half-reactions in acidic solution: 2 i− arrow i2 + 2 e− (oxidized) and 2 io3− + 10 e− arrow i2 (reduced)?
h+ + i− + io3 arrow i2 + 3 h2o
6 h+ + 5 i− + io3− arrow 3 i2 + 3h2o
5 h+ + i− + io3 arrow i2 + 3 h2o (my answer)
i− + io3 arrow i2 + 3 h2o

in their compounds, metals:
are assigned positive oxidation numbers
are assigned negative oxidation numbers
are assigned oxidation numbers of zero
can be assigned any oxidation number that balances the equation (my answer)