<span>Anthracite is also referred to as hard coal because it is so hard and pure. It is very hard and highly compacted with variety of coal that has submetallic luster. It has highest carbon content, the lowest impurities, and highest density of energy of all the coal deposits.</span>
They move fast enough to overcome the forces of attraction that hold them together, becoming a gas.
ITS THAT :)
The volume is 100mL.
The mass is 1.5kg which is equal to 1500g.
Thus, the density is 1500g / 100mL which is 15g/mL.