If gaseous H2 and O2 are carefully mixed and left alone, they can remain intact for millions of years. Is this “stability” a function of thermodynamics or of kinetics? Give a valid reason to support your choice.
The stability of gaseous H2 and O2 when mixed is primarily a function of kinetics rather than thermodynamics.
Kinetics deals with the rate at which reactions occur, while thermodynamics focuses on the energy changes that occur during a reaction. In this case, if the H2 and O2 gases were thermodynamically unstable, they would react immediately to form water (H2O), as this would lower their energy and increase stability.
However, the reaction between H2 and O2 to form water requires a high activation energy. Without an external source of energy, such as a flame or spark, the reaction between H2 and O2 is too slow to occur within a reasonable timeframe. The activation energy acts as a barrier that prevents the reaction from proceeding readily and keeps the gases intact when carefully mixed and left alone.
Therefore, the fact that gaseous H2 and O2 can remain intact for millions of years when mixed is mostly due to the low kinetic energy of the molecules and the high activation energy required for the reaction to occur, rather than any thermodynamic stability associated with the mixture.
The "stability" of gaseous H2 and O2 when carefully mixed and left alone for millions of years can be attributed to the thermodynamics rather than kinetics.
Thermodynamics deals with the study of energy and its transformations in a system, while kinetics focuses on the rate at which reactions occur. In this case, the stability being referred to relates to the absence of a reaction between H2 and O2, keeping them intact for a long period.
A valid reason to support this assertion is the fact that the reaction between H2 and O2 to form water (2H2 + O2 -> 2H2O) is highly exothermic, meaning it releases a large amount of energy. However, for this reaction to occur, it requires a certain activation energy, which is usually overcome by the presence of a spark or flame. Without this activation energy being supplied, the reaction rate remains extremely low.
So, although the reaction between H2 and O2 is thermodynamically favorable, the high activation energy barrier prevents the reaction from occurring at a significant rate. Therefore, the stability observed in the mixture is primarily a function of thermodynamics, as the thermodynamic favorability of a reaction determines the potential energy change associated with the reaction.