Copper metal can be produced by heating copper(II) oxide and hydrogen gas (and other product of the reaction is water)

Question

If the enthalpy of reaction () for this reaction is +130.5 kJ, calculate the heat of reaction for producing 2.0 g of copper metal.

Answer 1

CuO(s) + H₂(g) ==> Cu(s) + H₂O(g) ... ∆Hrxn = +130.5 kJ

The given ∆H is for the reaction as written, i.e. it is for 1 mole of CuO producing 1 mole Cu. Since 2.0 g Cu is produced, we can find the ∆H for that reaction as well...

2.0 g Cu x 1 mol Cu/63.55 g = 0.0315 moles Cu

0.315 mol Cu x 130.5 kJ/mol Cu = 4.1 kJ for this reaction