Today's organic photovoltaic cells shows a higher efficiency greater that 20 percentage. What are the important sources for this efficiency?

20:9

Purification of copper can be achieved by electrorefining copper from an impure copper anode onto a pure copper cathode in an electrolytic cell. How many hours will it take to plate 18.5 kg of copper onto the cathode if the current passed through the cell is held constant at 40.5 A? Assume the copper in the electrolytic solution is present as Cu?+. time: * TOOLS x10

hromium can be electroplated from aqueous potassium dichromate, with the reduction shown below. If a current of  6.0 A and a voltage of 9.6 V are used: How many kilowatt-hours of electrical energy are required to plate 2.56 g of chromium? The molar mass of chromium is 52.00 g/mol. Hint:  Check the units to know the required factors to arrive at kWh.

The gold plating of a ceramic figurine requires a total of 4.19 g of solid gold.  If the current being used is 11.0 amperes, how many minutes will it take to plate the gold figurine?  You may assume that there is a sufficient concentration of gold cation to complete the process.

Let’s assume that a first-generation Tesla Powerwall is made up of battery cells that use graphite (C6 ) in the anode and lithium cobalt oxide (LiCoO2 ) in the cathode. Each cell’s capacity is 2.7 Ah and has a voltage of 4.4 V. Assume the Powerwall’s total storage capacity is 7.00 kWh, the energy content of 1 gram of graphite is 370 mAh/g, and the energy content of 1 gram of LiCoO2 is 137 mAh/g. How many lithium ions are in the Powerwall? What is the mass (in grams) of lithium per Powerwall? Assume 1.0 lithium ion per unit charge (100% of lithium atoms go through the oxidation reduction reaction) and the molar mass of lithium is 6.94 g/mol. One unit charge (q) is 1.6x(10^-19) coulombs, and one coulomb is one Ampere-second.

The following metals could be used in the photovoltaic cell described above (mark all that could be used): Choose one or more: O potassium ( = 3.78 × 10-19 J) O silver ( = 7.59 × 10-19 J) O silicon ( = 7.24 x 10-19 J) O titanium ( = 6.94 × 10-19 J) %3D O tungsten ( = 7.20 × 10-19 J) O barium ( = 4.29 × 10-19 J)

If 3.47 grams of silver have been plated on a piece of metal from an AgNO3 solution after 6.95 minutes, what was the current (in amps) used to accomplish this?

Consider a fuel cell that uses methane ("natural gas") as fuel. The reaction is                         CH4 + 2O2 → 2H2O +CO2 Assuming ideal performance, how much electrical work can you get out of the cell, for each mole of methane fuel?

Consider the voltaic cell illustrated in Figure 20.5, which is based on the cell reaction Zn1s2 + Cu2+1aq2 ¡ Zn2+1aq2 + Cu1s2 Under standard conditions, what is the maximum electrical work, in joules, that the cell can accomplish if 50.0 g of copper is formed?