What are the answers to these three questions?
1. Consider the following half-reaction.
4H+(aq) + O2(g) + 4e- → 2H2O(l) Eo = 1.23 V
What is E, if the pressure of oxygen gas is 1.0 atmosphere and the pH is 8.30?
2. The activation energy for a particular reaction is 98 kJ/mol. By what factor will the rate constant increase when the temperature is increased from 50 oC to 65 oC?
3. Balance the following half-reaction in base, using smallest whole number coefficients. What is the coefficient for OH- in the balanced equation?
CrO42-(aq) → Cr(OH)3(s)
1. pH = -log(H^+) = 8.30. Plug (H^+) into the below equation.
E = Eocell - (0.05916/4) log[(H2O)^2/(H^+)^*pO2]
Post your work if you get stuck.
2. 50 C is 273 + 50 = 323 K and 65 C is 273 + 65 = 338 K.
ln (rate 2/rate 1) = Ea (1/T1 - 1/T2)/R
Plug in the values and solve for the ratio.
3.
CrO42-(aq) + 3e + 4H2O→ Cr(OH)3(s) + 5OH^-
Post your work if you get stuck.