Advertisements
Advertisements
Question
For a certain reaction ΔH° = 219 kJ and ΔS° = –21 J/K. Determine whether the reaction is spontaneous or nonspontaneous.
Advertisements
Solution
Given:
∆H0 = 219kJ; ∆S0 = -21 J/K, ∆G0 = ?
For the standard state, T = 298 K
∆G0 = ∆H0 - T∆S0
= 219 - 298 × (-21) × 10-3
= 219 + 6.258
= 225.3 kJ
Since ∆S < 0 and ∆G0 > 0, the reaction is non-spontaneous.
APPEARS IN
RELATED QUESTIONS
Define entropy.
In which of the following, entropy of the system decreases?
Answer the following in one or two sentences.
State second law of thermodynamics in terms of entropy.
Answer the following in one or two sentences.
Comment on the spontaneity of reactions for which ∆H is positive and ∆S is negative.
Obtain the relationship between ∆G° of a reaction and the equilibrium constant.
Answer in brief.
What is entropy? Give its units.
Answer the following question.
Although ΔS for the formation of two moles of water from H2 and O2 is –327J K–1, it is spontaneous. Explain.
(Given ΔH for the reaction is –572 kJ).
One mole of NaCl(s) on melting absorbed 30.5 kJ of heat and its entropy increased by 28.8 J K−1. The melting point of NaCl is ____________.
A system is changed from an initial state to a final state by a manner such that ∆H = Q. If the change from initial state to final state was made by a different path, then ____________.
For a process, entropy change of a system is expressed as ________.
For a reversible spontaneous change, ∆S is ____________.
In how many of the following, ∆S is positive?
i. Melting of ice
ii. Sublimation of iodine
iii. Dissolution of CuSO4 in water
iv. Condensation of water vapour
v. Dissociation of H2 molecule into atoms
vi. Conversion of carbon dioxide gas to dry ice
vii. Vaporization of acetone
Which of the following conditions indicates the reaction is spontaneous?
At what temperature, a chemical reaction will have the following values of ∆G, ∆S and ∆H?
∆G = −5.2 KJ mol−1, ∆H = 145.6 kJ mol−1, ∆S = −216 kJ mol−1
Which of following is residual entropy of a substance?
Standard molar entropy is ______.
The H-H bond energy is 430 kJ mol-1 and Cl-Cl bond energy is 240 kJ mol-1. ΔfH for HCl is - 90 kJ, then H-Cl bond energy is ______.
Relation between ΔH and ΔU for the reaction, \[\ce{2SO_{3(g)} -> 2SO_{2(g)} + O_{2(g)}}\] is _______.
Identify the unit used for measurement of energy according to international system of units?
A reaction is spontaneous at low temperatures but non-spontaneous at high temperatures. Which of the following is true for the reaction?
Write the correct condition for spontaneity in terms of Gibbs energy.
Identify whether the following pair have a larger entropy or not. If yes then Why?
O2{g) at 1 atm or O2(g) at 10 atm both at the same temperature.
Write the relationship between Gibbs energy change for a process and total entropy change of system and surroundings.
Calculate ΔG for ΔH = − 110 kJ, ΔS = + 40 J K−1 at 400 K.
ΔH for the reaction is − 110 kJ, and ΔS is + 40 JK−1 at 400 K. The free energy change for the reaction is ______.
The entropy of vaporisation of benzene is 85 J K−1 mol−1. When 117 g of benzene vaporises at its boiling point, what is the entropy change of the surroundings if the process is at equilibrium?
