Section 20.1 the meaning of oxidation and reduction answer key

Oxidation is defined as the reaction in which there is loss of electrons. It  is accompanied by increase in oxidation number.

Fe being the pure element in its standard state has oxidation number of zero and on loosing electron changes to oxidation number of +2.

Reduction is defined as the reaction in which there is gain of electrons. It  is accompanied by decrease in oxidation number.

Iron changes from oxidation number of +2 to pure iron [Fe} with oxidation number of zero.

chemistry sucks a**

explanation:

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3