For the combustion reaction of ethylene
(c2h4)
ch4 + 302 + 2 co2 + 2h20
assume all reactants and products are gases,
and calculate the ahxn using the following
ah values (in kj/mol):
ahch, = 52
ahco, = -393
aho, = 0
ahⓡ4,0 = –242

elements make up everything, and they combine to make compounds.

the answer is c

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.