When heated,mercury(II)oxide decomposes into elemental mercury and oxygen: 2 HgO(s)→ 2 Hg(l)+ O₂(g)ΔH° = 181.6 kJ ΔS° = 216.4 J/K Estimate the temperature at which HgO should begin to decompose if the partial pressure of O₂(g)is constant at 1.00 atm.

Question

Quizplus · Accepted Answer

To estimate the temperature at which HgO should begin to decompose, we can use the equation:

ΔG° = ΔH° - TΔS°

where ΔG° is the change in Gibbs free energy, ΔH° is the change in enthalpy, ΔS° is the change in entropy, and T is the temperature in kelvin.

At the temperature where ΔG° = 0, the reaction is at equilibrium and the forward and reverse reactions occur at equal rates. This temperature is called the equilibrium constant, K, and is related to ΔG° by the equation:

ΔG° = -RT ln K

where R is the gas constant and T is the temperature in kelvin.

For the decomposition of HgO, we can write the equilibrium constant as:

K = (PO2)/(PHg^2)

where PO2 is the partial pressure of oxygen and PHg is the partial pressure of mercury vapor. At constant pressure, we can assume that PO2 = 1 atm. We also know that the standard free energy change for the reaction is:

ΔG° = -RT ln K = 181.6 kJ/mol

Substituting in the values for R and ln K, we can solve for T:

T = -ΔG°/(R ln K) = 566°C

Therefore, the correct answer is C) 566°C.

When Heated,mercury(II)oxide Decomposes into Elemental Mercury and Oxygen: 2 HgO(s)→