Advertisements
Advertisements
Question
Answer the following in one or two sentences.
State whether ΔS is positive, negative or zero for the reaction 2H(g) → H2(g). Explain.
Advertisements
Solution
ΔS is negative. Two moles of gaseous H atoms are converted into 1 mole of H2 gas. Thus, a disorder of the system decreases, and hence, entropy decreases, or ∆S is negative.
APPEARS IN
RELATED QUESTIONS
Define entropy.
In which of the following, entropy of the system decreases?
Answer the following in one or two sentences.
Comment on the spontaneity of reactions for which ∆H is positive and ∆S is negative.
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).
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?
Equilibrium constant for a reaction is 20. What is the value of ΔG° at 300 K? (R = 8 x 10-3 kJ)
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)
For the reaction:
\[\ce{2Cl_{(g)} -> Cl2_{(g)}}\]
Which one of the following has ΔS0 greater than zero?
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.
The equilibrium constant for a reaction is 10, value of ΔG° at 300 K is (R = 8 × 10-3 kJ)
For which of the following reaction, ΔH = ΔU?
In which of the following reaction the value of Kp will be equal to Kc?
Write the correct condition for spontaneity in terms of Gibbs energy.
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.
What is a spontaneous process? What are its characteristics?
Calculate ΔG for ΔH = − 110 kJ, ΔS = + 40 J K−1 at 400 K.
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?
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.
Define second law of thermodynamics.
