Answer: The vapor pressure of naphthalene within the flask remains at atm.
Explanation:
The transformation from solid naphthalene to its gaseous form follows the equilibrium reaction:
- The formula employed to determine the enthalpy change for the reaction is:
The formula for calculating the enthalpy change regarding the aforementioned reaction is:
The provided information includes:
Substituting the values into the previous equation produces:
- The formula utilized to compute Gibbs free energy change is of a reaction:
The equation for the enthalpy change for the reaction is:
The given factors include:
By inserting values from the above equation, we arrive at:
- For the calculation of
(at 25°C) regarding the provided value of Gibbs free energy, the following relationship is applied:
where,
= Gibbs free energy = 22.5 kJ/mol = 22500 J/mol (Conversion factor: 1kJ = 1000J)
R = Gas constant =
T = temperature =
= equilibrium constant at 25°C =?
Inserting values into the above equation yields:
- To determine the equilibrium constant at 35°C, we refer to the equation proposed by Arrhenius, which states:
where,
= Equilibrium constant at 35°C =?
= Equilibrium constant at 25°C =
= Enthalpy change of the reaction = 72.1 kJ/mol = 72100 J
R = Gas constant =
= Initial temperature =
= Final temperature =
By plugging values into the equation above, we obtain:
- In order to calculate the partial pressure of naphthalene at 35°C, we utilize the equation for
, which is:
The partial pressure of the solid phase is considered to be 1 at equilibrium.
Therefore, the value for will equal
Consequently, the partial pressure of naphthalene at 35°C is atm.