Carbon (c) and hydrogen (h) are pure substances. each is made of only one type of atom, but carbon atoms are different from hydrogen atoms. carbon and hydrogen chemically combine to form methane (ch4). based on this information, a. carbon, hydrogen, and methane are all compounds. b. methane is an element and carbon and hydrogen are compounds. c. carbon and hydrogen are elements and methane is a compound. d. carbon, hydrogen, and methane are all elements.

C.  

carbon and hydrogen are elements and methane is a compound.

C. carbon and hydrogen are elements and methane is a compound.

Explanation:

Elements are substances which have one type of atoms. Compounds are substances which have different types of atoms. Since, Carbon and Methane have only one type of atoms and thus, these are pure substances. Methane  contains atoms of Carbon and Hydrogen chemically combined together. Thus, methane is a compound.

that would be b i just took the test : )

multiply 2kg by latent heat of vap