Advertisements
Advertisements
प्रश्न
Answer the following in one or two sentences.
Comment on the spontaneity of reactions for which ∆H is positive and ∆S is negative.
Advertisements
उत्तर
When ∆H positive and ∆S is negative, then ∆G is positive regardless of temperature. Such reactions are nonspontaneous at all temperatures.
APPEARS IN
संबंधित प्रश्न
Define entropy.
In which of the following, entropy of the system decreases?
Answer the following in one or two sentences.
State whether ΔS is positive, negative or zero for the reaction 2H(g) → H2(g). Explain.
Answer the following in one or two sentences.
If the enthalpy change of a reaction is ∆H how will you calculate the entropy of surroundings?
Equilibrium constant for a reaction is 20. What is the value of ΔG° at 300 K? (R = 8 x 10-3 kJ)
Identify the INCORRECT statement.
Arrange the following in order of increasing entropy.
I. 1.0 mol H2O (298 K, 1 atm)
II. 1.0 mol H2O (270 K, 1 atm)
III. 1.0 mol H2O (400 K, 1 atm)
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
In which of the following, ∆S is positive?
For the following reaction:
\[\ce{Fe2O3_{(s)} + 3CO_{(g)} -> 2Fe_{(s)} + 3CO2_{(g)}}\]; ΔH0 = −29.8 kJ and ΔS0 = 15 J K−1. What is the value of \[\ce{ΔS_{(total)}}\] at 298 K?
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
For a reaction to be non-spontaneous at all temperatures, values of ΔH and ΔS respectively are ____________.
Which of following is residual entropy of a substance?
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 ______.
The equilibrium constant for a reaction is 10, value of ΔG° at 300 K is (R = 8 × 10-3 kJ)
For a reaction ΔH = - 30kJ and ΔS = - 45 JK-1, at what temperature reaction changes from spontaneous to non-spontaneous?
For which of the following reaction, ΔH = ΔU?
The criterion for a spontaneous process is ______.
Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are −382.64 kJ mol−1 and −145.6 JK−1 mol−1, respectively. Standard Gibb's energy change for the same reaction at 298 K is ______.
Identify whether the following pair have larger entropy or not. If yes then Why?
He(g) in a volume of 1 L or He(g) in a volume of 5 L both at 25°C.
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.
Identify whether the following pair have a larger entropy or not. If yes then Why?
C2H5OH(l) or C2H5OH(g)
What is a spontaneous process? What are its characteristics?
ΔH for the reaction is − 110 kJ, and ΔS is + 40 JK−1 at 400 K. The free energy change for the reaction is ______.
For a certain reaction ΔH0 is −224 kJ and ΔS0 is −153 J K−1. At what temperature the change over from spontaneous to non-spontaneous will occur?
