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At 298 K , ∆H = 520.0 kJ and ∆S = 184 J/K for the reaction shown below. MnO2(s)  ⟶ Mn(s) + O2(g) (a) Use the data to decide if this reaction is spontaneous at 298 K. [a] (b) What is the temperature above which the reaction is spontaneous? [b]

Calculate the molar solubility of M2X (Ksp = 1.3 x 10-21) in pure water. M2X(s) ⇌ 2M+(aq) + X2-(aq)

In the titration of 20.0 mL of 0.150 M HNO3 with 0.300 M NaOH, calculate the pH after the addition of 10.0 mL of NaOH. HNO3(aq) + NaOH(aq) → NaNO3(aq) + H2O(l)

Use the standard free energies of formation (∆Gof) data to calculate the equilibrium constant for the reaction at 298 K. 2AB(g) ⇌ A2(g) + B2(g) Substance (state) ∆Gof (kJ/mol) A2(g) 0 B2(g) 0 AB(g) -10.0

What is the cell potential at 25oC for the concentration cell described by: Cu(s) | Cu2+(aq, 0.15 M) || Cu2+(aq, 0.75 M) | Cu(s)

The pH of a 1.75 M solution of weak acid HA is 3.25. Calculate the value of Ka for HA.

For a certain reaction at 330 K, ∆Hsys = 9.9 kJ and ∆Ssys = 85 J/K, calculate ∆Suniv.

Calculate ΔG°rxn for the following reaction at 525 K. CH2O(g) +  2H2(g) → CH4(g)   +  H2O(g) ΔH° = -94.9 kJ;  ΔS° = -224.2 J/K Answer: ΔG°rxn  = [a] kJ

Determine the standard entropy change (∆So) for this reaction. 2HgO(s) ⟶2Hg(l) + O2(g) Substance (state) So (J/mol.K) HgO(s) 70.3 Hg(l) 75.9 O2(g) 205.2  

Use the following values to calculate ∆S for the sublimation of 1 mole of I2. I2(s) ⟶I2(g) Substance (state) So (J/mol.K) I2(s) 116.1 I2(g) 260.7