<span>N2, penta means 5, so 5 oxygens
so with that being said n205</span>
An extinction event is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. It occurs when the rate of extinction increases with respect to the rate of speciation. -Wikipedia
Density = mass / volume
Mass = 5 kg
Volume = 50 cm³
d = 5 / 50
d = 0,1 kg/cm³