Base your answers to questions 83 through 85 on the information below
and on your knowledge of chemistry.
scientists defined oxidation as a chemical reaction in which oxygen
combined with another element to produce an oxide of the element. An
example of oxidation based on this definition is the combustion of
methane. This reaction is represented by the balanced equation below.
Equation 1: CH4(g) + 2O2(g)
→ CO2(g) + 2H2O(g)
The definition of oxidation has since been expanded
to include many reactions that do not involve oxygen. An example of
oxidation based on this expanded definition is the reaction between
magnesium ribbon and powdered sulfur when heated in a crucible. This
reaction is represented by the balanced equation below.
Equation 2: Mg(s) + S(s) → MgS(s)
83 State why early scientists classified the reaction
represented by equation 1 as oxidation. 
|Answer--> Oxides are formed.
A substance reacts with oxygen.Zn to the Cu.....Right
84 Determine the change in oxidation number of
carbon in equation 1. 
85 Write a balanced half-reaction equation for
the oxidation that occurs in the reaction represented by equation 2.