Read the following chemical equations.
reaction 1: h2s+cl-> 2hcl+s
reaction 2: fe+s-> fes
which of the following statements if true for both the chemical equations?
a) chlorine is reduced in reaction 1 and iron is reduced 2
b) chlorine is oxidized in reaction 1 and iron is oxidized in reaction 2
c) chlorine is oxidized in reaction 1 and iron is reduced in reaction 2
d) chlorine is reduced in reaction 1 and iron is oxidized in reaction 2

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.