Advertisements
Advertisements
प्रश्न
Answer in brief.
What is entropy? Give its units.
Advertisements
उत्तर
- Entropy is a measure of molecular disorder or randomness.
- An entropy change of a system is equal to the amount of heat transferred (Qrev) to it in a reversible manner divided by the temperature (T) in Kelvin at which the transfer takes place. Thus,
`triangle "S" = ("Q"_"rev")/"T"` - Units of entropy: J K–1
Note: Entropy or its change ∆S is a state function and depends on the initial and final states of the system and not on the path connecting two states
APPEARS IN
संबंधित प्रश्न
Define entropy.
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.
State second law of thermodynamics in terms of entropy.
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?
Obtain the relationship between ∆G° of a reaction and the equilibrium constant.
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).
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.
For a reversible spontaneous change, ∆S is ____________.
In which of the following, ∆S is positive?
For the reaction:
\[\ce{2Cl_{(g)} -> Cl2_{(g)}}\]
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?
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?
Which of following is residual entropy of a substance?
For which of the following reaction, ΔH = ΔU?
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 ______.
In which of the following reaction the value of Kp will be equal to Kc?
Dinitrogen and dioxygen combined to form nitrous oxide in equilibrium at 850 K. The equilibrium constant for this reaction is 0.56. If the equilibrium concentration of nitrous oxide gas is 3 × 10-3 M and both dinitrogen and dioxygen have the same concentration, then what will be the concentration of dinitrogen gas in M?
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.
Find out the value of equilibrium constant for the following reaction at 298 K, \[\ce{2NH3_{(g)} + CO2_{(g)} ⇌ NH2 - COONH2_{(aq)} + H2O_{(l)}}\] Gibbs Standard energy change 298 K = –13.6 kJ mol−1.
