The molar specific heat Cv = R s / 2
70.6 J/mol.K = (8.314 J/mol.K) * s / 2
So the number of degrees of freedom are:
s = 16.98 = 17
The answer is D. To put it simply, all atom wished to become stable. The only way for that is to obtain an octet structure where the outermost shell would have 8 electrons, thus being full.
Answer: Charles's law, Avogadro's law and Boyle's law.
Justification:
Boyle's law states that at constant temperature PV = constant
Charles law states that at constant pressure V/T = constant
Avogadro's law states that at constant pressure ant temperature, equal volume of gases contain equal number of moles: V/n = constant
Ideal gas law states PV/nT = constant => PV = nT*constant = PV = nTR