Answer:
w = 7376.6 J
Step-by-step explanation:
To calculate the work done in the system, we need first to calculate the number of moles of all compounds.
The following expression, that comes from the 1° law of thermodynamic, will help you to get the work:
w = ΔnRT
Where:
Δn: difference in the number of moles between products and reactants
R: constant universal of gases (8.314 J / mol K)
T: Temperature in Kelvin.
As we are doing this reaction in STP, then the Pressure is 1 atm, and temperature is 0 °C or 273 K.
Now, we already have the moles of Cu₂O, let's see, according to the balanced reaction, how many moles we should have of O₂ and CuO.
If 1 mole of O₂ reacts with 2 moles of Cu₂O then 6.5 moles of Cu₂O will be:
moles O₂ = 6.5 moles Cu₂O * (1 mole O₂/2 moles Cu₂O) = 3.25 moles O₂
If 2 moles of Cu₂O produces 4 moles of CuO, then 6.5 moles will be:
moles CuO = 6.5 moles Cu₂O*(4 moles CuO/2 moles Cu₂O) = 13 moles CuO
Now that we have the moles, let's calculate the value of Δn.
Δn = moles product - moles reactants
Δn = 13 - (6.5 + 3.25) = 3.25 moles
Now, we can calculate the work done in the system:
w = 3.25 * (8.314 * 273)
w = 7376.6 J or 7.3766 kJ
Hope this helps