Free Energy: Equilibrium Constant and Temperature Effects

Which is true for a spontaneous process? ΔSsys>0 ΔSuniv>0 ΔGsys>0 ΔGsys<0

ΔSuniv>0 ΔGsys<0

Of the following, which is not true of a system at equilibrium? K= e^RT/ΔG∘ Q= K ΔG∘= −RTlnK None of the above

K= e^RT/ΔG∘

If ΔG∘<0, _______. reactants are more abundant at equilibrium K>1 reactants and products are equally abundant at equilibrium K=1

K>1

What must be true of a system where reactants are more abundant at equilibrium? Keq>1, ΔG∘<0 Keq<1, ΔG∘>0 Keq=1, ΔG∘=0 depends on the temperature

Keq<1, ΔG∘>0

Which of the following four equilibrium constant values indicates the greatest (largest positive) free energy change at standard conditions? Keq=0.15 Keq=0.2 Keq=1.5 Keq=2

Keq=0.15 (The free energy change at equilibrium is positive for values of K less than 1, and the equation ΔG=−RTlnK indicates that the smaller the absolute value of K for a reaction, the greater (more positive) the value of ΔG for that reaction. So, the reaction with the largest numerical free energy change is the one in which K=0.15)

What term is best described as the change in free energy for a process occurring at constant temperature and pressure? Standard energy change Standard Gibbs change Standard free energy change None of the above

Standard free energy change

Gibbs free energy depends on: enthalpy entropy temperature all of the above

all of the above

Which of the following is a state function? G S H all of the above

all of the above

Any process with a positive change in enthalpy(+ΔH) and a negative change in entropy(-ΔS) will be: spontaneous nonspontaneous spontaneous at high temperatures spontanteous at low temperatures

nonspontaneous

If ΔG∘>0, _______. K>1 products are more abundant at equilibrium reactants and products are equally abundant at equilibrium reactants are more abundant at equilibrium

reactants are more abundant at equilibrium

Free energy change is a reliable indicator of ___________ in a process. spontaneity external energy kinetic energy none of the above

spontaneity

Any process with a negative change in enthalpy(-ΔH) and a positive change in entropy(+ΔS) will be: spontaneous nonspontaneous spontaneous at high temperatures spontanteous at low temperatures

spontaneous

If, for a particular process, ΔH=54 kJ/mol and ΔS=312 J/(mol)(K), the process will be: spontaneous at any temperature nonspontaneous at any temperature spontaneous above a certain temperature spontaneous below a certain temperature

spontaneous above a certain temperature

A process with a negative change in enthalpy(-ΔH) and a negative change in entropy(-ΔS) will generally be: spontaneous nonspontaneous spontaneous above a certain temperature spontaneous below a certain temperature

spontaneous below a certain temperature

When considering the effects of temperature on spontaneity, if both ΔH and ΔS are positive, _______. a) the process is spontaneous at all temperatures b) the process is nonspontaneous at all temperatures c) the process is spontaneous above a certain temperature and nonspontaneous below d) the process is spontaneous below a certain temperatures and nonspontaneous above

the process is spontaneous above a certain temperature and nonspontaneous below

If ΔH is negative and ΔS is positive, _______. a) the process is spontaneous at all temperatures b) the process is spontaneous at low temperatures and nonspontaneous at high temperatures c) the process is nonspontaneous at all temperatures d) the process is spontaneous at high temperatures and nonspontaneous at low temperatures

the process is spontaneous at all temperatures

For an equilibrium where the forward and reverse reactions are equally spontaneous, the Gibbs free energy change is: negative zero positive negative or positive, depending on the temperature of the system

zero

When looking at the free energy change for a process involving a system at equilibrium, the change in free energy will be: positive negative zero depends on the temperature

zero

If K>1, _______. ΔG∘ is negative ΔG∘ is positive reactants and products are equally abundant at equilibrium reactants are more abundant at equilibrium

ΔG∘ is negative

Choose the option below that is not necessarily true of a system at equilibrium. ΔG∘= 0 ΔG∘= −RTlnK Q= K ΔG= 0

ΔG∘=0

Under which of the following conditions is a process spontaneous at high temperatures and nonspontaneous at low temperatures? ΔH and ΔS are both positive ΔH and ΔS are both negative ΔH is positive and ΔS is negative ΔH is negative and ΔS is positive

ΔH and ΔS are both positive

Temperature affects spontaneity because in the equation for free energy change T is multiplied by: ΔH ΔS ΔG none of the above

ΔS

The change in Gibbs free energy may be equated to: TΔSsys −TΔSsys TΔSuniv −TΔSuniv

−TΔSuniv