How many electrons would be exchanged in the iron-oxygen redox reaction?
electrons

Twelve electrons are exchanged in the iron-oxygen redox reaction.

Explanation:

Oxidation and reduction reactions are complementary processes. Every oxidation must be accompanied by a reduction and vice versa. In fact, the both processes are not essentially different but are different aspects of the same process hence the coinage 'redox reaction'.

In the redox reaction under consideration, iron is the electron donor while oxygen is the electron acceptor. The half equations are shown below;

Oxidation half equation;

4Fe---> 4Fe^3+ + 12e

Reduction half equation;

3O2 + 12e > 6O^2-

Ionic equation of the process;

4Fe^3+ + 6O^2- > 2Fe2O3

Hence it can be clearly seen that twelve electrons were transferred in the process.

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.