Advertisements
Advertisements
प्रश्न
Answer the following question.
Determine whether the following reaction is spontaneous under standard state conditions.
2H2O(l) + O2(g) → 2H2O2(l)
if ΔH° = 196 kJ, ΔS° = –126 J/K, does it have a cross-over temperature?
उत्तर
When ∆H positive and ∆S is negative, then ∆G is positive regardless of temperature. Hence, the reaction is nonspontaneous at all temperatures. It does NOT have a cross-over temperature.
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 second law of thermodynamics in terms of entropy.
Obtain the relationship between ∆G° of a reaction and the equilibrium constant.
For a certain reaction ΔH° = 219 kJ and ΔS° = –21 J/K. Determine whether the reaction is spontaneous or nonspontaneous.
Equilibrium constant for a reaction is 20. What is the value of ΔG° at 300 K? (R = 8 x 10-3 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 ____________.
Identify the INCORRECT statement.
What is the entropy change (in J K−1 mol−1) when one mole of ice is converted into water at 0°C? (The enthalpy change for the conversion of ice to liquid water is 6.0 kJ mol−1 at 0°C)
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
For the reaction:
\[\ce{2Cl_{(g)} -> Cl2_{(g)}}\]
Which one of the following has ΔS0 greater than zero?
Heat of combustion of C(s), H2(g) and C2H6(g) are −x1, −x2 and −x3 respectively. Hence heat of formation of C2H6(g) is ____________.
Equilibrium constant for a reaction is 20. What is the value of ∆G0 at 300 K? (R = 8 × 10−3 kJ)
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
If ΔH° and ΔS° for the reaction \[\ce{N2O_{4(g)} -> 2NO_{2(g)}}\] is 57.24 kJ and 175.8 JK-1 mol-1 respectively. What is the value of ΔG° for this reaction at 298 K?
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 ______.
When will be change in Gibb's free energy always negative?
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.
Give quantitative definition of entropy. Give its units.
Calculate ΔG for ΔH = − 110 kJ, ΔS = + 40 J K−1 at 400 K.
Define second law of thermodynamics.
