A.) Calculate the enthalpy change, ΔH, for the processin which 37.9 g of water is converted from liquid at 4.6 ∘C tovapor at 25.0 ∘C .
For water, ΔHvap = 44.0 kJ/mol at 25.0 ∘C andCs = 4.18 J/(g⋅∘C) for H2O(l).
B.)How many grams of ice at -29.4 ∘C can be completely convertedto liquid at 20.7 ∘C if the available heat for this process is5.90×103 kJ ?
For ice, use a specific heat of 2.01 J/(g⋅∘C) andΔHfus=6.01kJ/mol.
C.)In the following experiment, a coffee-cup calorimetercontaining 100 mL of H2O is used. The initial temperature of thecalorimeter is 23.0 ∘C. If 4.20 g of CaCl2 is added to thecalorimeter, what will be the final temperature of the solution inthe calorimeter? The heat of solution ΔHsoln of CaCl2 is−82.8 kJ/mol.
D.)
Calculate the standard enthalpy change for the reaction
2A+B⇌2C+2D
Use the following data:
| Substance | ΔH∘f
(kJ/mol) |
| A | -255 |
| B | -413 |
| C | 223 |
| D | -485 |
Express your answer to three significant figures and include theappropriate units.
