The reaction of an organic compound, like a hydrocarbon, as it burns in the presence of oxygen is called

combustion

Explanation: When a compound burns in the presence of oxygen the reaction is called a combustion. Like most organic substances, hydrocarbons are combustible. The general reaction is given below. Organic Compound + O 2 (g) ! CO 2 (g) + H 2 O(g) + Heat=Energy (1)

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