Suppose that 2.25 grams of X (MW 20.5) are dissolved in 602 mL of water, and the water %3D temperature changes from 21.8°C to 23.01°C. Assume that the mass of X is negligible compared to the mass of the water. Assume the specific heat of water is 4.2 J/(g.°C) and the density of water is 1.0 g/mL. Calculate the enthalpy of dissolution of X in kJ/mol. Report your answer to three decimal places.

Suppose that 2.25 grams of X (MW 20.5) are dissolved in 602 mL of water, and the water %3D temperature changes from 21.8°C to 23.01°C. Assume that the mass of X is negligible compared to the mass of the water. Assume the specific heat of water is 4.2 J/(g.°C) and the density of water is 1.0 g/mL. Calculate the enthalpy of dissolution of X in kJ/mol. Report your answer to three decimal places.

Chemistry: Principles and Reactions

8th Edition

ISBN:9781305079373

Author:William L. Masterton, Cecile N. Hurley

Publisher:William L. Masterton, Cecile N. Hurley

Chapter8: Thermochemistry

Section: Chapter Questions

Problem 11QAP: When one mol of KOH is neutralized by sulfuric acid, q=56 kJ. (This is called the heat of...

See similar textbooks

Similar questions

Benzoic acid, C6H5COOH, is a common standard used in bomb calorimeters, which maintain a constant volume. If 1.20 g of benzoic acid gives off 31, 723 J of energy when burned in the presence of excess oxygen and in a water bath having a temperature of 24.6 C, calculate q, w, H, and U for the reaction.
Magnesium sulfate is often used in first-aid hot packs, giving off heat when dissolved in water. A coffee-cup calorimeter at 25C contains 15.0 mL of water at 25C. A 2.00-g sample of MgSO4 is dissolved in the water and 1.51 kJ of heat are evolved. (You can make the following assumptions about the solution: volume=15.0 mL, density=1.00 g/mL, specific heat=4.18J/gC.) (a) Write a balanced equation for the solution process. (b) Is the process exothermic? (c) What is qH2O? (d) What is the final temperature of the solution? (e) What are the initial and final temperatures in F?
In a coffee-cup calorimeter, 100.0 mL of 1.0 M NaOH and 100.0 mL of 1.0 M HCI are mixed. Both solutions were originally at 24.6C. After the reaction, the final temperature is 31.3C. Assuming that all the solutions have a density of 1.0 g/cm3 and a specific heat capacity of 4.18 J/Cg, calculate the enthalpy change for the neutralization of HCl by NaOH. Assume that no heat is lost to the surroundings or to the calorimeter.
When 1.000 g of ethylene glycol, C2H6O2, is burned at 25C and 1.00 atmosphere pressure, H2O(l) and CO2(g) are formed with the evolution of 19.18 kJ of heat. a Calculate the molar enthalpy of formation of ethylene glycol. (It will be necessary to use data from Appendix C.) b Gf of ethylene glycol is 322.5 kJ/mol. What is G for the combustion of 1 mol ethylene glycol? c What is S for the combustion of 1 mol ethylene glycol?
The enthalpy of vaporization for water is 40.65 kJ mol-1. As a design engineer for a project in a desert climate, you are exploring the option of using evaporative cooling. (a) If the air has an average volumetric heat capacity of 0.00130 J cm-3 K-1, what is the minimum mass of water that would need to evaporate in order to cool a 5 m? 5 m room with a 3 m ceiling by 5°F using this method? (b) Is this a spontaneous or nonspontaneous process?
Would the amount of heat absorbed by the dissolution in Example 5.6 appear greater, lesser, or remain the same if the heat capacity of the calorimeter were taken into account? Explain your answer.
When one mol of KOH is neutralized by sulfuric acid, q=56 kJ. (This is called the heat of neutralization.) At 23.7C, 25.0 mL of 0.475 M H2SO4 is neutralized by 0.613 M KOH in a coffee-cup calorimeter. Assume that the specific heat of all solutions is 4.18J/gC, that the density of all solutions is 1.00 g/mL, and that volumes are additive. (a) How many mL of KOH is required to neutralize H2SO4? (b) What is the final temperature of the solution?
You did an experiment in which you found that 59.8 J was required to raise the temperature of 25.0 g of ethylene glycol (a compound used as antifreeze in automobile engines) by 1.00 K. Calculate the specific heat capacity of ethylene glycol from these data.
Peanuts and peanut oil are organic materials and bum in air. How many burning peanuts does it take to provide the energy to boil a cup of water (250 mL of water)? To solve this problem, we assume each peanut, with an average mass of 0.73 g, is 49% peanut oil and 21% starch; the remainder is noncombustible We further assume peanut oil is palmitic acid, C16H32O2, with an enthalpy of formation of 848.4 kJ/mol. Starch is a long chain of C6H10O5 units, each unit having an enthalpy of formation of 960 kJ.
9.102 A runner generates 418 kJ of energy per kilometer from the cellular oxidation of food. The runner's body must dissipate this heat or the body will overheat. Suppose that sweat evaporation is the only important cooling mechanism. If you estimate the enthalpy of evaporation of water as 44 kJ/mol and assume that sweat can he treated as water, describe how you would estimate the volume of sweat that would have to be evaporated if the runner runs a 10-km race.
The octane number of gasoline is based on a comparison of the gasolines behavior with that of 2,2,4-trimethylpentane, C8H18(), which is arbitrarily assigned an octane number of 100. The standard enthalpy of combustion of this compound is 5456.6 kJ/mol. (a) Write the thermochemical equation for the combustion of 2,2,4-trimethylpentane. (b) Use the standard enthalpies of formation in Appendix G to calculate the standard enthalpy of formation of 2,2,4-trimethylpentane.
What is the change in internal energy when a gas contracts from 377mL to 119mLundera pressure of 1550 torr, whileat the same time being cooled by removing 124.0J ofheat energy?