Chapter 3, Problem 3.37SP

Which of the following equations are balanced? Balance any that need it.

(a) The thermite reaction, used in welding:

${\text{Al+Fe}}_{\text{2}}{\text{O}}_{\text{3}}\to {\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}\text{+Fe}$

(b) The photosynthesis of glucose from CO₂:

${\text{6CO}}_{\text{2}}{\text{+6H}}_{\text{2}}\text{O}\to {\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}{\text{+6O}}_{\text{2}}$

(c) The separation of gold from its ore:

${\text{Au+2NaCN+O}}_{\text{2}}{\text{+H}}_{\text{2}}\text{O}\to {\text{NaAu(CN)}}_{\text{2}}\text{+3NaOH}$