The standard free energy of formation of nitric oxide, NO, at 1000.K (roughly the temperature in an automobile engine during ignition)is 77.7 kJ/mol. Calculate the equilibrium constant for the reaction N2 (g) + O2 (g) 2NO(g) At 1000.K.(R = 8.31 J/(K ∙ mol))
A)0.95
B)7.6 × 10-9
C)1.6 × 105
D)-15
E)8.7 × 10-5

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.