Gibbs free energy (
G ) is a state function defined with regard to system quantities only and may be used to predict the spontaneity of a process. A negative value for Δ
G indicates a spontaneous process; a positive Δ
G indicates a nonspontaneous process; and a Δ
G of zero indicates that the system is at equilibrium. A number of approaches to the computation of free energy changes are possible.
Key equations
Δ
G = Δ
H −
T Δ
S
Δ
G = Δ
G ° +
RT ln
Q
Δ
G ° = −
RT ln
K
Chemistry end of chapter exercises
What is the difference between Δ
G , Δ
G °, and
for a chemical change?
A reactions has
= 100 kJ/mol and
Is the reaction spontaneous at room temperature? If not, under what temperature conditions will it become spontaneous?
The reaction is nonspontaneous at room temperature.
Above 400 K, Δ
G will become negative, and the reaction will become spontaneous.
Use the standard free energy of formation data in
Appendix G to determine the free energy change for each of the following reactions, which are run under standard state conditions and 25 °C. Identify each as either spontaneous or nonspontaneous at these conditions.
Use the standard free energy data in
Appendix G to determine the free energy change for each of the following reactions, which are run under standard state conditions and 25 °C. Identify each as either spontaneous or nonspontaneous at these conditions.
(a) Determine the standard free energy of formation,
for phosphoric acid.
(b) How does your calculated result compare to the value in
Appendix G ? Explain.
(a) −1124.3 kJ/mol for the standard free energy change. (b) The calculation agrees with the value in
Appendix G because free energy is a state function (just like the enthalpy and entropy), so its change depends only on the initial and final states, not the path between them.
Step 1: Find the mean. To find the mean, add up all the scores, then divide them by the number of scores. ...
Step 2: Find each score's deviation from the mean. ...
Step 3: Square each deviation from the mean. ...
Step 4: Find the sum of squares. ...
Step 5: Divide the sum of squares by n – 1 or N.
The sample of 16 students is taken. The average age in the sample was 22 years with astandard deviation of 6 years. Construct a 95% confidence interval for the age of the population.
Bhartdarshan' is an internet-based travel agency wherein customer can see videos of the cities they plant to visit. The number of hits daily is a normally distributed random variable with a mean of 10,000 and a standard deviation of 2,400
a. what is the probability of getting more than 12,000 hits?
b. what is the probability of getting fewer than 9,000 hits?
Bhartdarshan'is an internet-based travel agency wherein customer can see videos of the cities they plan to visit. The number of hits daily is a normally distributed random variable with a mean of 10,000 and a standard deviation of 2,400.
a. What is the probability of getting more than 12,000 hits