3.106 Copper is an excellent electrical conductor widely un in making electric circuits. In producing a printed circ board for the electronics industry, a layer of copper laminated on a plastic board. A circuit pattern is th printed on the board using a chemically resistant pc mer. The board is then exposed to a chemical bath t reacts with the exposed copper, leaving the desired c per circuit, which has been protected by the overlay polymer. Finally, a solvent removes the polymer. One action used to remove the exposed copper from the cuit board is Cu(s) + Cu(NH),Cl2(aq) + 4 NH3(aq) - 2 Cu(NH3)CH A plant needs to produce 5000 circuit boards, each w a surface area measuring 2.0 in. x 3.0 in. The boards covered with a 0.65-mm layer of copper. In subsequ processing. 85% of the copper is removed. Copper he density of 8.96 g/cm'.Calculate the masses of Cu(NE Cl2 and NH3 needed to produce the circuit boards. suming that the reaction used gives a 97% yield.

How long would it take to plate 6.49 g of nickel onto copper using a 2.0 V power supply with a 437 mA current flow and 0.50 M nickel (II) acetate solution? time in (hr)

Chemistry Explain why manganese which has an average minimum exploitable grade of 35% has a higher concentration factor compared to gold which has an average minimum exploitable grade of 0.0001%.

0.0123 g of the powder from the tablet ( 1.4770g) was  transferred to a 100 mL volumetric flask. 20 mL of 1M hydrochloric acid was added to the flask. The volume in the flask was then made up to the mark with deionized water which was filtered. 40 mL of the filtrate and 4 mL of a lanthanum chloride solution were placed into a large test tube. Half of the prepared sample was  spiked with a 20 mg/L calcium standard. The calibration standards and the unknown sample solutions were then measured for calcium concentration at 422.7 nm with flame atomic absorption spectroscopy.  Each tablet is stated by the manufacturer to contain 500 mg of calcium.   Sample ID         Absorbance Blank                 0.039Reagent Blank   0.194Sample              0.855Spiked sample   1.184Calibration curve: y = 0.0184x + 0.007; r2 = 0.991   Calculate the spike recovery for the calcium analysis.