4what is the net amount of heat released when two moles of c2h6(g) are formed from its elements at 101.3 kpa and 298 k?

i know the final answer is -168 bc somehow you get -84 from somewhere i'm just not sure where that comes from.

If a solution is considered basic, then a) the hydroxide ion and hydronium ion concentrations are equal. b) the hydroxide ion concentration is less than the hydronium ion concentration. c) the hydronium ion concentration is greater than the hydroxide ion concentration. d) the hydroxide ion concentration is greater than the hydronium ion concentration.

Describing intermolecular forces use the drop down menus to match the type of intermolecular force to its name dipole dipole interactions dipole induced dipole interactions london dispersion forces hydrogen bond van der waals forces done

What happens to isotopes that are unstable?