capacity of the bomb calorimeter. (3) -...
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November 11, 2012
1. A 1.55 g of CH4O sample is burnt in a calorimeter. If the molar heat of combuson of CH4O is ‐725 kJ/mole, and assuming that the 2.00 L of water absorbed all of the heat of combuson, what temperature change did the water experience (c water = 4.184J/gC)? (3)
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November 11, 2012
1. In order to obtain calibraon data for a bomb calorimeter, three 2.50 g samples of methanol were burned. The average temperature change of 4.23°C was recorded. The molar heat of combuson of methanol is ‐726 kJ/mol. Calculate the heat capacity of the bomb calorimeter. (3)
![Page 3: capacity of the bomb calorimeter. (3) - Coursesmrrumbolt.weebly.com/uploads/4/9/5/2/4952485/u1a2solutions.pdf · capacity of the bomb calorimeter. (3) ... Notes,Whiteboard,Whiteboard](https://reader031.vdocuments.site/reader031/viewer/2022012401/5adad5487f8b9a52528d5ecb/html5/thumbnails/3.jpg)
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November 11, 2012
1. A student dropped 5.00 g of an unknown acid HX, into 75.0 ml of aqueous Lithium Hydroxide, LiOH(s),. The reacon mixture absorbed 525 J as it warmed. Assuming it had a specific heat capacity of
4.184 :a. what was the temperature change of the reacon mixture?
(Hint: what is the mass of the new soluon?) (3)b. What was the molar enthalpy of reacon for the acid,
assuming a molar mass of 36.46 g/mol. (3)
![Page 4: capacity of the bomb calorimeter. (3) - Coursesmrrumbolt.weebly.com/uploads/4/9/5/2/4952485/u1a2solutions.pdf · capacity of the bomb calorimeter. (3) ... Notes,Whiteboard,Whiteboard](https://reader031.vdocuments.site/reader031/viewer/2022012401/5adad5487f8b9a52528d5ecb/html5/thumbnails/4.jpg)
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November 11, 2012
1. Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: (4)
N2H4(l) + CH4O(l) → CH2O(g) + N2(g) + 3H2 (g)ΔH = ?
2NH3(g) → N2H4(l) + H2(g) ΔH = 22.5 kJ
2NH3(g) → N2(g) + 3H 2(g) ΔH = 57.5 kJ
3CH2O(g) + 3H2(g) → 3CH 4O(l) ΔH = 243.6 kJ
![Page 5: capacity of the bomb calorimeter. (3) - Coursesmrrumbolt.weebly.com/uploads/4/9/5/2/4952485/u1a2solutions.pdf · capacity of the bomb calorimeter. (3) ... Notes,Whiteboard,Whiteboard](https://reader031.vdocuments.site/reader031/viewer/2022012401/5adad5487f8b9a52528d5ecb/html5/thumbnails/5.jpg)
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November 11, 2012
1. A 275 g aluminum can is filled with 100.0 mL of water and suspended over a peanut. Calculate the fuel value of peanuts if burning a peanut with a mass of 0.358 g caused the temperature of the water to rise +5.46°C. (Hint: the aluminum can
AND the water absorb heat) (4)
![Page 6: capacity of the bomb calorimeter. (3) - Coursesmrrumbolt.weebly.com/uploads/4/9/5/2/4952485/u1a2solutions.pdf · capacity of the bomb calorimeter. (3) ... Notes,Whiteboard,Whiteboard](https://reader031.vdocuments.site/reader031/viewer/2022012401/5adad5487f8b9a52528d5ecb/html5/thumbnails/6.jpg)
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November 11, 2012
1. A. Use enthalpies of formaon to calculate the molar enthalpy for the reacon below. (4)
2 NH3(g) + 2 CH4(g) + 3 O2(g) à 2 HCN(g) + 6 H2O(l)
Enthalpies of formaon:
NH3(g) = ‐46.19 kJ/mol CH4(g) = ‐74.86 kJ/mol HCN(g) = +130.5 kJ/mol H2O(l) = ‐285.9 kJ/mol
![Page 7: capacity of the bomb calorimeter. (3) - Coursesmrrumbolt.weebly.com/uploads/4/9/5/2/4952485/u1a2solutions.pdf · capacity of the bomb calorimeter. (3) ... Notes,Whiteboard,Whiteboard](https://reader031.vdocuments.site/reader031/viewer/2022012401/5adad5487f8b9a52528d5ecb/html5/thumbnails/7.jpg)
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November 11, 2012
b. Use bond energies to calculate the enthalpy value for the above reacon. (4)
N‐H (389 kJ/mol); C‐H (414 kJ/mol); O=O (494 kJ/mol) CN (879 kJ/mol); O‐H (463 kJ/mol)
c. Compare the values for the molar enthalpy in a and b. Account for any similaries and differences. (2)
2 NH3(g) + 2 CH4(g) + 3 O2(g) à 2 HCN(g) + 6 H2O(l)
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November 11, 2012
1. Using bond energies from the table below, determine the enthalpies of combuson. (6)
a. Cyclobutene,
b. Ethanoic Acid
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November 11, 2012
1. Using bond energies from the table below, determine the enthalpies of combuson. (6)
a. Cyclobutene,
b. Ethanoic Acid
![Page 10: capacity of the bomb calorimeter. (3) - Coursesmrrumbolt.weebly.com/uploads/4/9/5/2/4952485/u1a2solutions.pdf · capacity of the bomb calorimeter. (3) ... Notes,Whiteboard,Whiteboard](https://reader031.vdocuments.site/reader031/viewer/2022012401/5adad5487f8b9a52528d5ecb/html5/thumbnails/10.jpg)
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November 11, 2012
1. For the following reacon:
P(s) + 5/2 Cl2(g) à PCl5(s) ∆Hrxn = ‐910 KJ/mol
Determine the energy of the P‐Cl bond. Cl‐Cl = 240KJ/mol. (4)