At 298 K , ∆H = -198.4 kJ and ∆S = -187.9 J/K for the reaction shown below. 2SO2(g)  +  O2(g) ⟶ 2SO3(g) (a) Use the data to decide if this reaction is spontaneous at 298 K. [a] (b) What is the temperature below which the reaction is spontaneous? [b]

A 0.300 M solution of a weak base, B, has a pH of 9.75. Calculate the value of Kb for the base. Hint: Write the reaction between the base B and water (B + H2O → BH+ + OH-), and use on ICE Table. You must show all of your work for credit.

Predict the sign (∆S > 0 or ∆S < 0) of the entropy change (∆S) for the following processes. (a) Pb2+(aq) + S2-(aq) ⟶ PbS(s) [a] (b) CO2(s) ⟶ CO2(g)[c] (c) 4Fe(s) + 3O2(g) ⟶ 2Fe2O3(s) [e]

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

Calculate the cell potential of a voltaic cell, which consists of a Sn/Sn2+ half-cell and a Fe/Fe2+ half-cell. Sn2+ + 2 e⁻  →  Sn Eo = -0.14 V Fe2+ + 2 e⁻  →  Fe Eo = -0.44 V

What is the cell potential at 25oC for the concentration cell described by: Cu(s) | Cu2+(aq, 0.10 M) || Cu2+(aq, 0.80 M) | Cu(s) You must show all of your work for credit!

Consider the following reaction: N2O4(g) ⇌ 2NO2(g)   Kp = 47.9 at 400 K Suppose that 1.00 atm of N2O4 decomposes and reaches equilibrium at 400 K. Determine the partial pressure of NO2 at equilibrium. Show all of your work including the ICE chart for credit.

For the titration of 10.0 mL of 0.200 M HCl with 0.100 M NaOH. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) a) What is the initial pH? pH =  [a] b) What is the pH after the addition of 5.00 mL of NaOH ? pH =  [b] c) What is the pH after the addition of 20.0 mL of NaOH? pH =  [c] d) What is the pH after the addition of 25.0 mL of NaOH? pH =  [d]

Calculate the pH of a solution with a hydroxide ion concentration of 5.25

Calculate the pH of a buffer containing 2.50 M formic acid, HCOOH (Ka = 1.8 × 10-4) and 1.25 M sodium formate, HCOONa.You must show all of your work for credit.