Given the reaction at equilibrium:
X + Y = 2Z + heat
The concentration of the product could be
increased by
A. adding a catalyst
B. adding more heat to the system
C. increasing the concentration of Y
D. decreasing the concentration of X

b. is the answer hoped i        

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.  

d : a person who learns about the world by observing it. no that is not a smiley face

explanation: