Given the following info, complete the calculation of Hfor the reactions of Mg a

Question

Given the following info, complete the calculation of Hfor the reactions of Mg and MgO. Assume the ractions are carriedout in a calorimeter containing 100 mL H2O. Then use the data tocalculate the enthalpy of formation of MgO in kcal/mol. Mg: Initial temp: 23.0 degrees C Final temp: 32.8 degrees C Weight of Mg ribbon: 0.2401 g H = ________ kcal/mol MgO: Initial temp: 23.0 degrees C Final temp: 25.8 degrees C Weight of MgO: 0.4404 g H = ________ kcal/mol Enthalpy of formation of MgO = _________ kcal/mol Given the following info, complete the calculation of Hfor the reactions of Mg and MgO. Assume the ractions are carriedout in a calorimeter containing 100 mL H2O. Then use the data tocalculate the enthalpy of formation of MgO in kcal/mol. Mg: Initial temp: 23.0 degrees C Final temp: 32.8 degrees C Weight of Mg ribbon: 0.2401 g H = ________ kcal/mol MgO: Initial temp: 23.0 degrees C Final temp: 25.8 degrees C Weight of MgO: 0.4404 g H = ________ kcal/mol Enthalpy of formation of MgO = _________ kcal/mol

Explanation / Answer

We Know that :    H = mass of the substance xspecific heat x change in temperature            = 0.2401 gm x 0.24378 cal / gm K x (305.8 -296) K             = 1.030134 cal.              = 1030.134 x 10-3 Kcal / mol     H = mass of thesubstance x specific heat x change in temperature              = 0.4404 gm x 0.89625 cal / gm 0 C x (25.8-23.0)0C              =  0.173829 cal               = 173.829 x 10-3 Kcal / mol      Enthalpy of formation of MgO is   Hproducts   - H reactants                     Mg + O2 ------> MgO               Hrxn    =    173.829 x 10-3 Kcal / mole - 1030.134 x10-3 Kcal                             = -856.305 x 10-3 Kcal / mole

Related Questions

Navigate

• Browse (All)
• Browse G
• Subjects

---

---

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