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Entropy change of the surroundings and total entropy change

This type of question, asked 7 times: 11 May 2024 S2, 14 May 2024 S1, 19 Apr 2025 S1, 19 Apr 2025 S2, 26 Apr 2025 S1, 16 Apr 2026 S1, 19 May 2026 S2. All 7 questions below, oldest first.

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  1. Question 1

    11 May 2024 S2

    95
    Calculate ΔStotal\Delta S_\text{total} for the following reaction at 300 K. NH4NO3(s)→NH4+(aq)+NO3−(aq)\text{NH}_4\text{NO}_3(s) \to \text{NH}_4^+(aq) + \text{NO}_3^-(aq); ΔH=28.1 kJ mol−1\Delta H = 28.1\text{ kJ mol}^{-1}, ΔSsys=108.7 J K−1mol−1\Delta S_\text{sys} = 108.7\text{ J K}^{-1}\text{mol}^{-1}

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  2. Question 2

    14 May 2024 S1

    53
    If enthalpy change for following reaction at 300 K is +7 kJ mol−1+7\,\text{kJ mol}^{-1}, find the entropy change of surrounding? H2O(s)⟶H2O(l)\text{H}_2\text{O}_{(s)}\longrightarrow\text{H}_2\text{O}_{(l)}

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  3. Question 3

    19 Apr 2025 S1

    68
    Calculate ΔStotal \Delta S_{\text{total~}} for a certain reaction at 298 K if ΔH∘=−208.6 kJ\Delta H^{\circ}= - 208.6\text{ }kJ and ΔS∘=−36 J K−1\Delta S^{\circ}= - 36\text{ }J{\text{ }K}^{- 1}

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  4. Question 4

    19 Apr 2025 S2

    65
    Calculate the entropy change of surrounding if 2 moles of H2H_{2} and 1 mole of O2O_{2} gas combine to form 2 moles of liquid water by releasing 525 kJ heat to surrounding at constant pressure and at 300 K .

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  5. Question 5

    26 Apr 2025 S1

    98
    Calculate ΔStotal \Delta S_{\text{total~}} for a certain reaction if ΔH=−150 kJ\Delta H = - 150\text{ }kJ and ΔS=32JK−1\Delta S = 32JK^{- 1} at 300 K .

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  6. Question 6

    16 Apr 2026 S1

    7
    What is the change in entropy of surrounding for the reaction, H2(g)+1/2 O2(g)→H2O(l)\mathrm{H_{2(g)} + 1/2\,O_{2(g)} \rightarrow H_2O_{(l)}} at 298 K if standard enthalpy of formation of water is −286-286 kJ ?

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  7. Question 7

    19 May 2026 S2

    6
    Calulate ΔS(total)\Delta S_{(total)} for following reaction. CH3OH(l)+3/2 O2(g)→CO2(g)+2H2O(l)\mathrm{CH_3OH_{(l)} + 3/2\,O_{2(g)} \to CO_{2(g)} + 2H_2O_{(l)}}, ΔH=−726 kJ mol−1\Delta H = -726\ \mathrm{kJ\ mol^{-1}}, ΔS(system)=42 JK−1\Delta S_{(system)} = 42\ \mathrm{JK^{-1}} (both at 298298 K)

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