Advertisements
Advertisements
प्रश्न
For a certain reaction ΔH° = 219 kJ and ΔS° = –21 J/K. Determine whether the reaction is spontaneous or nonspontaneous.
Advertisements
उत्तर
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
संबंधित प्रश्न
Define entropy.
In which of the following, entropy of the system decreases?
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?
Answer the following in one or two sentences.
Comment on the spontaneity of reactions for which ∆H is positive and ∆S is negative.
Answer the following question.
Obtain the relation between ΔG and `triangle "S"_"total"`. Comment on the spontaneity of the reaction.
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 ____________.
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 which of the following, ∆S is positive?
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 ____________.
Which of the following conditions indicates the reaction is spontaneous?
Equilibrium constant for a reaction is 20. What is the value of ∆G0 at 300 K? (R = 8 × 10−3 kJ)
For a reaction to be non-spontaneous at all temperatures, values of ΔH and ΔS respectively are ____________.
Calculate the amount of heat liberated during formation of 2. 7 kg of water if heat of formation of water is - 284.5 kJ mol-1.
For a reaction ΔH = - 30kJ and ΔS = - 45 JK-1, at what temperature reaction changes from spontaneous to non-spontaneous?
When will be change in Gibb's free energy always negative?
A reaction is spontaneous at low temperatures but non-spontaneous at high temperatures. Which of the following is true for the reaction?
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 ______.
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.
Identify whether the following pair have a larger entropy or not. If yes then Why?
C2H5OH(l) or C2H5OH(g)
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?
Define second law of thermodynamics.
