Spontaneous example sentences

Then, what drives the spontaneous process in a given direction ? Let us examine such a case in which ?H = 0 i.e., there is no change in enthalpy, but still the process is spontaneous.In pregnant women who have the habit of smoking the increased CO level in blood may induce premature birth, spontaneous abortions and deformed babies.In fact, all naturally occurring processes whether chemical or physical will tend to proceed spontaneously in one direction only.It is clear from the discussion in previous sections that neither decrease in enthalpy nor increase in entropy alone can determine the direction of spontaneous change for these systems.We may ask 'what is the driving force of spontaneously occurring changes ? What determines the direction of a spontaneous change ? In this section, we shall establish some criterion for these processes whether these will take place or not.If it is not, the system would spontaneously change to configureuration of lower free energy.They move less spontaneously or make odd grimaces and gestures.These and many other spontaneously occurring changes show unidirectional change.We may summarise it as follows: A spontaneous process is an irreversible process and may only be reversed by some external agency.We can say that entropy for a spontaneous process increases till it reaches maximum and at equilibrium the change in entropy is zero.By analogy, we may be tempted to state that a chemical reaction is spontaneous in a given direction, because decrease in energy has taken place, as in the case of exothermic reactions.But heat will not flow from colder body to warmer body on its own, the gas in a container will not spontaneously contract into one corner or carbon dioxide will not form carbon and dioxygen spontaneously.Another aspect of spontaneous reaction or process, as we see is that these cannot reverse their direction on their own.Their spontaneous demonstration, in thousands, around the courthouse was the beginning of their liberation from fear of the British.We may now formulate another postulate: in an isolated system, there is always a tendency for the systems' energy to become more disordered or chaotic and this could be a criterion for spontaneous change ! At this point, we introduce another thermodynamic function, entropy denoted as S.