Question

In the context of the Haber process, where the enthalpy change (ΔH) is given as -92.4 kJ/mol, the textbook solution calculates the entropy change in the surroundings (ΔS_surr) using the formula ΔS_surr = -ΔH / T, with T = 25 degrees Celsius. However, the problem did not explicitly state whether the reaction is reversible. Why can this formula be used, and is it valid even if the reaction is irreversible?

a.The formula can be used regardless of whether the reaction is reversible or irreversible; it's a general expression for entropy change.
b.The formula is applicable only for reversible reactions; its use in irreversible reactions would lead to inaccuracies.
c.The formula can be used for irreversible reactions, but the value obtained may not accurately represent the entropy change.
d.The use of this formula is not appropriate without information about the reversibility of the reaction.

Answer 1

The formula ΔS_surr = -ΔH / T can be used for both reversible and irreversible reactions. It reflects the general relationship between enthalpy change in the system and entropy change in the surroundings. Temperature should be in Kelvin for this calculation. The correct answer is: a.

Step-by-step explanation:

The formula ΔSsurr = -ΔH / T can be used regardless of whether the reaction is reversible or irreversible; it's a general expression for entropy change.

This is because the formula is based on the principle that when energy in the form of heat is transferred out of or into a system, it impacts the entropy of the surroundings.

The temperature used in the formula must be in Kelvin, so if the problem provides the temperature in degrees Celsius, it must be converted to Kelvin by adding 273.15.

The entropy (S) is a thermodynamic property that measures the degree of disorder in a system. The entropy change of the surroundings (ΔSsurr) is directly related to the enthalpy change (ΔH) of the system, and it measures how the heat transferred during the reaction affects the disorder of the surrounding environment. The correct answer is: a.