A plate having an area of 10 cm ^2 is to be electroplated with copper (density 9000 kg m ⁻³ ) to a thickness of 10 micrometres on both sides, utilising a 12 V cell. Determine the energy expended by the cell during the deposition process. If this energy is subsequently used to heat 100 g of water, determine the rise in the water's temperature. Given the ECE of copper is 3 10⁻⁷ kg C ⁻¹ and the specific heat capacity of

Step-by-step solution

Volume of copper deposited on both sides of the plate: V = 2 A t V = 2 (10 10⁻⁴ m ^2) (10 10⁻⁶ m ) = 2 10⁻⁸ m ^3 Mass of copper deposited: m = V = 9000 2 10⁻⁸ = 1.8 10⁻⁴ kg From Faraday's law of electrolysis: m = ZQ Q = m Z Q = 1.8 10⁻⁴ 3 10⁻⁷ = 600 C Energy expended by the cell: E = Q V_ cell = 600 12 = 7200 J = 7.2 kJ Rise in temperature of water: E = m_w s T 7200 = 0.1 4200 T T = 7200 420 = 120 7 17.14 K Thus, the energy expended is 7.2 kJ and the rise in temperature is approximately 17 K .