Anthracite, also known as hard coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.

When a gas is heated, change takes place in
* pressure
* volume
* temperature

Extensive properties The properties of the system, whose value for the entire system is equal to the sum of their values for the individual parts of the system, are called extensive properties.
For example, total volume, total mass and total energy of a system are extensive properties.

Intensive properties The properties of the system, whose value for the entire system is not equal to the sum of their values for the individual parts of the system, are called intensive properties.
For example, temperature, pressure and density of a system are intensive properties.