MISSED THIS? Watch IWE: Measuring AHrxn in a Coffee- Cup Calorimeter, Read Section 7.7. You can click on the Review link to access the section in your e Text. Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic reaction: NH₂NO3(s) → NH; (aq) + NO3(aq) In order to measure the enthalpy change for this reaction, 1.25 g of NH, NO3 is dissolved in enough water to make 25.0 mL of solution. The initial temperature is 25.8 °C and the final temperature (after the solid dissolves) is 21.9 °C. Part A Calculate the change in enthalpy for the reaction. (Use 1.0 g/mL as the density of the solution and 4.18 J/(g-°C) as the specific heat capacity.) Express the enthalpy change in kilojoules per mole to two significant figures. 1ΨΕΙ ΑΣΦ ΔΗ, = Request Answer kJ/mol

MISSED THIS? Watch IWE: Measuring AHrxn in a Coffee- Cup Calorimeter, Read Section 7.7. You can click on the Review link to access the section in your e Text. Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic reaction: NH₂NO3(s) → NH; (aq) + NO3(aq) In order to measure the enthalpy change for this reaction, 1.25 g of NH, NO3 is dissolved in enough water to make 25.0 mL of solution. The initial temperature is 25.8 °C and the final temperature (after the solid dissolves) is 21.9 °C. Part A Calculate the change in enthalpy for the reaction. (Use 1.0 g/mL as the density of the solution and 4.18 J/(g-°C) as the specific heat capacity.) Express the enthalpy change in kilojoules per mole to two significant figures. 1ΨΕΙ ΑΣΦ ΔΗ, = Request Answer kJ/mol

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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9.96 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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