To calculate the mass of copper needed to produce the required voltage, we first need to determine the cell potential E_cell using the standard reduction potentials of copper E_Cu and aluminum E_Al . The cell potential can be calculated using the following equation:E_cell = E_cathode - E_anodeSince we want a positive cell potential, we will use copper as the cathode and aluminum as the anode:E_cell = -0.34 V - -1.66 V = 1.32 VNow, we need to increase the cell potential to at least 1.5 V. To do this, we can increase the mass of copper, which will increase the concentration of Cu ions in the solution and thus increase the cell potential. We can use the Nernst equation to determine the required concentration of Cu ions:E_cell = E_cell - RT/nF * ln Q where R is the gas constant 8.314 J/molK , T is the temperature in Kelvin assume 298 K for room temperature , n is the number of electrons transferred 2 for both Cu and Al redox reactions , F is Faraday's constant 96485 C/mol , and Q is the reaction quotient.Since we want to increase the cell potential to 1.5 V:1.5 V = 1.32 V - 8.314 J/molK * 298 K / 2 * 96485 C/mol * ln Q Solving for Q:ln Q = 1.5 V - 1.32 V * 2 * 96485 C/mol / 8.314 J/molK * 298 K ln Q 0.136Q 1.146For the reaction Cu + 2e Cu, Q = [Cu]. Therefore, the required concentration of Cu ions is approximately 1.146 M.Now, we can calculate the mass of copper needed to achieve this concentration. Assuming a 1 L 1000 cm solution:moles of Cu = 1.146 mol/L * 1 L = 1.146 molmass of Cu = moles of Cu * molar mass of Cumass of Cu = 1.146 mol * 63.55 g/mol 72.87 gSo, approximately 72.87 grams of copper is needed to produce the required voltage of 1.5 volts when aluminum is used as the other electrode.