A particular color of light has a wavelength of 663 nm. What is the energy possessed by the light? (Planck’s constant h=6.63×10−34h = 6.63 \times 10^{-34}h=6.63×10−34 J·s; Velocity of light c=3×108c = 3 \times 10^8c=3×108 m/s)
Consider the following cell: Pt(s) H2(1 atm)∣H+(1 M)∣Cr2O72−, Cr3+∣H+(1 M)∣Pt(s) \text{Pt}(s) \, \text{H}_2 (1 \, \text{atm}) | \text{H}^+ (1 \, \text{M}) | \text{Cr}_2\text{O}_7^{2-}, \, \text{Cr}^{3+} | \text{H}^+ (1 \, \text{M}) | \text{Pt}(s) Pt(s)H2(1atm)∣H+(1M)∣Cr2O72−,Cr3+∣H+(1M)∣Pt(s) Given: ECr2O72−/Cr3+∘=1.33 V,[Cr3+]2/[Cr2O72−]=10−7 E^\circ_{\text{Cr}_2\text{O}_7^{2-}/\text{Cr}^{3+}} = 1.33 \, \text{V}, \quad \left[ \text{Cr}^{3+} \right]^2 / \left[ \text{Cr}_2\text{O}_7^{2-} \right] = 10^{-7} ECr2O72−/Cr3+∘=1.33V,[Cr3+]2/[Cr2O72−]=10−7 At equilibrium: [Cr3+]2/[Cr2O72−]=10−7 \left[ \text{Cr}^{3+} \right]^2 / \left[ \text{Cr}_2\text{O}_7^{2-} \right] = 10^{-7} [Cr3+]2/[Cr2O72−]=10−7 Objective: Determine the pH at the cathode where Ecell=0. \text{Determine the pH at the cathode where } E_{\text{cell}} = 0. Determine the pH at the cathode where Ecell=0.