The fewer the carbon atoms, the closer it is to being a gas. The only one you have to check out is A which is hexane. You know that gasoline at the pumps has 8 carbons and its a liquid. So B and C are both not gases because they are above 8.
C6 (hexane) is a liquid at room temperature not a gas.
The answer is D. If there is a gas present, it must be C3
Compounds are not formed by accepting electrons. Number 1 and 3 are correct.
Answer: A. -396 kJ
Explanation:
The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states.
Reversing the reaction, changes the sign of 
On multiplying the reaction by 2, enthalpy gets multiplied by 2:
Thus the enthalpy change for the reaction is -396 kJ.
For a reaction to be spontaneous under standard conditions at all temperatures, the signs of ΔH° and ΔS° must be negative and positive, respectively.
<span>Gibbs free energy (G) determines if reaction will proceed
spontaneously, if </span>ΔG is negative, reaction is spontaneous.<span>
ΔG = ΔH - T·ΔS.
ΔG - changes in Gibbs free energy.
ΔH - changes in enthalpy.
ΔS - changes in entropy.
T is temperature in Kelvins.</span>
