The energy in Joules is calculated as:
E = VQ
At standard conditions, the standard potential or the voltage is equal to 0.76 V. Next, we have to determine Q. The formula is as follows:
Q = nF, where n is the number of moles electron, while F is the Faraday's constant (96,500 C/mol e)
From the given reaction, notice that Zn was converted to Zn²⁺, while Cu²⁺ to Cu. So, 1 mol Cu = 2 mol e.
Q = 51 g Cu (1 mol Cu/63.55 g)(2 mol e/1 mol Cu)(96,500 C/mol e)
Q = 154885.92 C
Thus,
E = (0.76 V)(154885.92 C)
E = 117,713.3 J
