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Spontaneity from the signs of dH and dS at a given temperature

This type of question, asked 4 times: 24 Jan 2023, 23 Jan 2025, 24 Jan 2025, 4 Apr 2025. All 4 questions below, oldest first.

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  1. Question 1

    24 Jan 2023

    53
    For independent processes at 300 K300\text{ }K:
    ProcessΔH/kJ mol−1\Delta H/kJ\,mol^{-1}ΔS/J K−1\Delta S/J\,K^{-1}
    A-25-80
    B-2240
    C25-50
    D2220
    The number of non-spontaneous processes from the above is ____\_\_\_\_.

  2. Question 2

    23 Jan 2025

    101
    The effect of temperature on spontaneity of reactions are represented as:
    ΔH\Delta H
    ΔS\Delta S
    		TemperatureSpontaneity
    (A)+-any TNon spontaneous
    (B)++low Tspontaneous
    (C)--low TNon spontaneous
    (D)-+any Tspontaneous

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  3. Question 3

    24 Jan 2025

    33
    Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boiling point of water. Choose the correct option.

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  4. Question 4

    4 Apr 2025

    27
    Let us consider a reversible reaction at temperature, T . In this reaction, both ΔH\Delta H and ΔS\Delta S were observed to have positive values. If the equilibrium temperature is Te , then the reaction becomes spontaneous at :

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