Instant cold packs used to treat athletic injuries contain solid NH, NO3 and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dissolves, lowering the temperature because of the endothermic reaction NH, NO3(s) + H₂O(1)→ NH4NO3(aq) AH = +257 kJ V Part A What is the final temperature in a squeezed cold pack that contains 42 5 g of NH, NO, dissolved in 125 mL of water? Assume a specific heat of 4.18J/(g° C) for the solution, an initial temperature of 30 0 °C, and no heat transfer between the cold pack and the environment. ΕΠΙ ΑΣΦ • A C E ? °C Request Answer Submit

Instant cold packs used to treat athletic injuries contain solid NH, NO3 and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dissolves, lowering the temperature because of the endothermic reaction NH, NO3(s) + H₂O(1)→ NH4NO3(aq) AH = +257 kJ V Part A What is the final temperature in a squeezed cold pack that contains 42 5 g of NH, NO, dissolved in 125 mL of water? Assume a specific heat of 4.18J/(g° C) for the solution, an initial temperature of 30 0 °C, and no heat transfer between the cold pack and the environment. ΕΠΙ ΑΣΦ • A C E ? °C Request Answer Submit

Chemistry for Engineering Students

4th Edition

ISBN:9781337398909

Author:Lawrence S. Brown, Tom Holme

Publisher:Lawrence S. Brown, Tom Holme

Chapter9: Energy And Chemistry

Section: Chapter Questions

Problem 9.96PAE: 9.96 Most first aid "cold packs" are based on the endothermic dissolution of ammonium nitrate in...

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9.83 A student performing a calorimetry experiment combined 100.0 mL of 0.50 M HCl and 100.0 mL of 0.50 M NaOH in a coffee cup calorimeter. Both solutions were initially at 20.0°C, but when the two were mixed, the temperature rose to 23.2°C. (a) Suppose the experiment is repeated in the same calorimeter but this time using 200 mL of 0.50 M HCl and 200.0 mL of 0.50 M NaOH. Will the T observed he greater than, less than, or equal to that in the first experiment, and why? (b) Suppose that the experiment is repeated once again in the same calorimeter, this time using 100 mL of 1.00 M HCl and 100.0 mL of 1.00 M NaOH. Will the T observed he greater than, less than, or equal to that in the first experiment, and why?
9.96 Most first aid "cold packs" are based on the endothermic dissolution of ammonium nitrate in water: NH4NO3(s)NH4+(aq)+NO3(aq) H= 25.69 kJ A particular cold pack contains 50.0 g of NH4NO3 and 125.0 g of water. When the pack is squeezed, the NH4NO3dissolves in the water. If the pack and its contents are initially at 24.0°C, what is the lowest temperature that this bag could reach? (Assume that the ammonium nitrate solution has a specific heat of 4.25J g-l K-l, and that the heat capacity of the bag itself is small enough to be neglected.)
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