The oxidation of copper(I) oxide, Cu2O(s), to copper(II) oxide, CuO(s), is an ex

Question

The oxidation of copper(I) oxide, Cu2O(s), to copper(II) oxide, CuO(s), is an exothermic process.

The change in enthalpy upon reaction of 91.36 g of Cu2O(s) is -93.22 kJ. Calculate the work, w, and energy change, ?Urxn, when 91.36 g of Cu2O(s) is oxidized at a constant pressure of 1.00 bar and a constant temperature of 25 °C.

e oxidation of copper(I) oxide, Cu20(s), to copper(lI) oxide, CuO(s), is an exothermic process. 2Cu2o(s) +02(g) 4Cuo(s) The change in enthalpy upon reaction of 91.36 g of Cu20(s) is -93.22 kJ Calculate the work, w, and energy change, AUrxn, when 91.36 g of Cu20(s) is oxidized at a constant pressure of 1.00 bar and a constant temperature of 25 °C. Number Note that AExn is sometimes used Number L as the symbol for energy change kJ LV rxn- k.J w= instead of AUxn. Tools

Explanation / Answer

Solution :-

Balanced reaction equation

2Cu2O(s) + O2(g) ---- > 4 CuO(s)

91.36 g Cu2O gives -93.22 kJ heat

Work = ?

Change in energy Delta U =?

Pressure = 1 bar = 0.9869 atm

Temperature = 25 C +273 = 298 K

Lets first calculate the moles of the Cu2O

Moles = mass / molar mass

Moles of Cu2O = 91.36 g / 143.091 g per mol = 0.63847 mol Cu2O

Now lets calculate the moles of the O2

1 mol O2 = 2 mol Cu2O

0.63847 mol Cu2O* 1 mol O2 / 2 mol Cu2O = 0.31923 mol O2

Now lets calculate the volume of the O2 using the ideal gas equation

PV= nRT

Where n = moles , P=pressure , T= Kelvin temperature , V= volume in L and R= gas constant (0.08206 L atm per K. mol )

V= nRT/P

V= 0.31923 mol * 0.08206 L atm per K. mol * 298 K / 0.9869 atm

V= 7.91 L atm

Now lets convert L atm to Joules

7.91 LK atm * 101.325 J / 1 L atm = 801 J

Convert Joules to kJ

801 J * 1 kJ / 1000 J = 0.801 kJ

Therefore the amount of work done = 0.801 kJ

Now lets calculate the change in the energy of the system

Delta U= q+W

q= -93.22 kJ

delta U = -93.22 kJ + 0.801 kJ

Delta U = -92.42 kJ

Therefore change in the energy = - 92.42 kJ

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.