o improve conductivity in the electroplating of automobile bumpers, a thin coating of copper separates the steel from a heavy coating of chromium. (a) What mass of Cu is deposited on an automobile trim piece if plating continues for 1.25 h at a current of 7.6 A

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

the complete reaction for the formation of aluminum oxide is as follows;

4al + 3 > 2

so if the molar mass of the is 32.0 g/mol and

so, to form 3.80 mol of

(3.80 mol ) x (3 mol ) x (32.0 g )

dividing by 2 because two moles of will be formed;

∴ 364.8/2   = 182.4g