Read the sentence. The same amount of matter exists before and after the change — none is created or destroyed.

How does this sentence contribute to the article's main idea?

A
It defines what is meant by the phrase "chemically the same."
B
It defines the concept of conservation of matter.
C
It explains why changing matter is important.
D
It explains that atoms have been around for a long time.

In vapor-liquid equilibrium in a binary mixture, both components are generally present in both phases. how many degrees of freedom are there for such a system? the reaction between nitrogen and hydrogen to form ammonia occurs in the gas phase. how many degrees of freedom are there for this system? steam and coal react at high temperatures to form hydrogen, carbon monoxide, carbon dioxide, and methane. the following reactions have been suggested as being involved in the chemical transformation: