Question

Calorimetry Problems: AH = m(at), Exercise #6: Enthalpy Problems 300 kg of water cools from 5 to 20 How much beat energy was released by the water? Co H2O(l) is 4.180 J/gºC. 4. How much heat energy is required to heat 45 g of sheet Fe from 24°C to 200."C?, of Fe(s) is 0.449 J/gºC. 3. A food chemist combusts 56 g of a chocolate bar in a calorimeter containing 1.5 L of water (density Ho mL). The initial temperature was 19°C and the final temperature was 73°C. How much heat energy was absorbed by the water? What was the AH... for this combustion reaction? 4. 5.00g of uranium is cooled from 55°C to 18°C. The heat released was 20.35 J (AH = -20.35 J). Calculate the specific heat capacity (c) for uranium. 5. Predict the final temperature of 15 L of water within a calorimeter when 10.0 g of potato chips are combusted. The initial temperature of the water was 19°C and the heat energy absorbed by the water .(released by the potato chips) was 62.8kJ (AH = 62.8kJ). Stoichiometry and AH Calculations 6. The heat of combustion for CH,O, is-2183.6kJ/mol C.H.O.. How much heat energy is released when 7.56 mol of C,H,O, are combusted? 7. In the above reaction, how much heat energy is released when 156.0 g of C,H,O, are combusted? 8. The AH for the following reaction is 58.2 kJ/mol rxn. N,0.9) 2 NO.(8) How many moles of NO, were produced if the AH was measured to be 3579 kJ? 9. The heat of combustion for CH, gas is -2510kJ/mol CH . How much heat energy is released if 59.3 g of Co, are produced. (Hint, you need to write and balance the equation.) 10. In the above reaction, how many moles of CH, and 0, would be required to release 4.6x10 kJ of heat energy? AH, Problems: AH..=EAH, products - ZAH, ruanto Use the Table of Heats of formation (AH) on the following page to calculate the AHan for the following reactions. 11. CaCO3(s) + Ca(s) + CO2(g) AH.-772 12. 4Fe(s) + O2(g) →2Fe2O3() AH.. ??? 13. NH,(g) + HF(g) NH F(s) AH -772 14.2F2(g) + 2H2O(1) + 4HF(g) + O2(g) AHxn=? 15. NH.NO3(s) N2O(g) + 2H2O(g) AH ??? 16.2C10H22(1) + 3102(g) +20002(g) + 22H2O(1) AH-7, where AHC Hz(1)--300.9kJ/mol 17. Calculate the AHp for MnBra(s) in the following reaction: 4HBr(s) + MnOr(s) MnBr(s) + 2H,00) + Bra(1) AHan-291.3 kJ (25°C) Hess's Law Problems: Adding & Subtracting Equations and AH. 18. Find the AH, for the decomposition of H2O2 into H20 and O2 using the following equations: 2H2(g) + O2(g) → 2H2O(1) AH..=-571.6kJ 2H2O2(1) -+2H2(g) +20,(g) AH = 375.6kJ 2H2O2(1)→2H2O(l) + O2(g) AH- Chem 400 Exercise 16 p. 1

Answer 1

2. We know, AH = m. At. Op where, AH = Heat energy, At = change in temperature ma mass of the substane e, a specific heat capacity Given, m=459. At = (200-24) c = 1760 p = 0.449 5/gie AH = 45% 176 x 0.449 J = 3556.08 J. 2.3556.08J. of heat energy is required to heat 45g of sheet Fe from 24 to 200°c,