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請大大們教我如何計算下列的題目??<大學>
20. When 0.7521 g of benzoic acid was burned in acalorimeter containing 1,000. g of water, a temperature rise of 3.60°C wasobserved. What is the heat capacity ofthe bomb calorimeter, excluding the water? The heat of combustion of benzoic acid is –26.42 kJ/g.39. Butane (C4H10)undergoes combustion in excess oxygen to generate gaseous carbon dioxide andwater. Given DH°f =–124.7 kJ/mol, DH°f = –393.5 kJ/mol, DH°f = –241.8 kJ/mol, howmuch energy is released (kJ) when 8.30 g of butane is burned?
75. A gas is compressed in a cylinder from a volumeof 20.0 L to 2.0 L by a constant pressure of 10.0 atm. Calculate the amount ofwork done on the system.
A) –1.81 × 104 J B) –180 J C) 180 J D) 1.01 × 104 J E) 1.81 × 104 J
81. At 25°C, the following heats of reaction areknown:
2ClF(g) + O2(g) ® Cl2O(g) + F2O(g) DH°rxn = 167.4 kJ/mol
2ClF3(g) + 2O2(g) ® Cl2O(g) + 3F2O(g) DH°rxn = 341.4 kJ/mol
2F2(g) + O2(g) ® 2F2O(g) DH°rxn = –43.4 kJ/mol
At the same temperature, use the above data to calculate the heat released (kJ) when 3.40 moles of ClF(g) reacts with excess F2:
ClF(g) + F2(g) ® ClF3(g)
82. The bond enthalpy of the Br–Cl bond isequal to DH° for the reaction
BrCl(g) ®Br(g) + Cl(g).
Use the following data to find thebond enthalpy of the Br–Cl bond.
Br2(l) ® Br2(g) DH° = 30.91 kJ/mol
Br2(g) ® 2Br(g) DH° = 192.9 kJ/mol
Cl2(g) ® 2Cl(g) DH° = 243.4 kJ/mol
Br2(l) + Cl2(g) ® 2BrCl(g) DH° = 29.2 kJ/mol
83. The heat of solution of ammonium nitrate is26.2 kJ/mol. If a 5.368 g sample of NH4NO3is added to 40.0 mL of water in a calorimeter at 23.5°C, what is the minimumtemperature reached by the solution? (The specific heat of water = 4.18 J/g·°C;the heat capacity of the calorimeter = 650. J/°C.)
A) –7.7°C B) 14.3°C C) 20.8°C D) 21.4°C E) 25.6°C
85. Aluminum oxide can be reduced to aluminum metalusing carbon, the other reaction product being carbon monoxide. Determine the enthalpy change when 12.5 g ofaluminum is produced by this method.
A) 310 kJ B) 361 kJ C) 697 kJ D) 725 kJ E) 1504 kJ
97. A 0.3423 g sample of pentane, C5H12,was burned in a bomb calorimeter. Thetemperature of the calorimeter and the 1.000 kg of water contained therein rosefrom 20.22°C to 22.82°C. The heatcapacity of the calorimeter is 2.21 kJ/°C. The heat capacity of water = 4.184J/g·°C. What is the heat of combustion,in kilojoules, per gram of pentane?
98. The heatof combustion of propane, C3H8, 2220 kJ/mol. The specificheat of copper is 0.385 J/g×°C. How manygrams of propane must be burned to raise the temperature of a 10.0 kg block ofcopper from 25.0°C to 65.0°C, assuming none of the heat is lost to thesurroundings
謝謝能教我的貴人
...<div class='locked'><em>瀏覽完整內容，請先 <a href='member.php?mod=register'>註冊</a> 或 <a href='javascript:;' onclick="lsSubmit()">登入會員</a></em></div><div></div> 20.
26420*0.7521 = 3.6 * (Cp water + Cp calorimeter)
39.
C4H10 + O2 => 4CO2 + 5H2O
DHrxn = 4*(-393.5)+5*(-241.8) - (-124.7)
Energy = 8.3 / (4*12+10) * DHrxn
75.
101325*10 * (20-2)*0.001 = 18238 => (E)
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