Chemists have been performing experiments with the newly discovered element X to determine its properties. Under standard conditions, X has been found to be a solid. They reacted element X with other elements to determine enthalpies of reaction. The value of AH° for the reaction below is - 191 kJ. 2 X(s) + Cl2 (g) → 2 XCI (g) What is the value of AH° for XCI (g) in kJ?

Chemists have been performing experiments with the newly discovered element X to determine its properties. Under standard conditions, X has been found to be a solid. They reacted element X with other elements to determine enthalpies of reaction. The value of AH° for the reaction below is - 191 kJ. 2 X(s) + Cl2 (g) → 2 XCI (g) What is the value of AH° for XCI (g) in kJ?

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter4: Energy And Chemical Reactions

Section: Chapter Questions

Problem 65QRT

See similar textbooks

Similar questions

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?
A 220-ft3 sample of gas at standard temperature and pressure is compressed into a cylinder, where it exerts pressure of 2000 psi. Calculate the work (in J) performed when this gas expands isothermally against an opposing pressure of 1.0 atm. (The amount of work that can be done is equivalent to the destructive force of about 1/4 lb of dynamite, giving you an idea of how potentially destructive compressed gas cylinders can be if improperly handled!)
For a process, w = 34 J and q = 109 J. What is E for this process?
It takes 2260 J to vaporize a gram of liquid water to steam at its normal boiling point of 100C. What is H for this process?What is the work, given that the water vaporexpands against a pressure of 0.988atm? What is U for thisprocess?
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?
Define the standard enthalpy of formation. What are standard states for elements and for compounds? Using Hess's law, illustrate why the formula Hreaction=npHf(products)nfHf(reactants) works to calculate H for a reaction.
What is the sign of the work when a refrigerator compresses a gas (the system) to a liquid during the refrigeration cycle?
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.
The reaction shown below is involved in the refining of iron. (The table that follows provides all of the thermodynamic data you should need for this problem.) 2Fe2O3(s)+3C(s,graphite)4Fe(s)+3CO2(g) (a) Find H for the reaction. (b) S for the reaction above is 557.98 J/K. Find S° for Fe2O3(s). (c) Calculate G for the reaction at the standard temperature of 298 K. (There are two ways that you could do this.) (d) At what temperatures would this reaction be spontaneous? Compound Hf (kJ mol-1) S° (kJ mol-1) Gf (J mol-1 K-1) Fe2O3(s) -824.2 ? -742.2 C(s, graphite) 0 5.740 0 Fe(s) 0 27.3 0 CO2(g) -393.5 213.6 -394.4.83
Nitromethane, CH3NO2, is a good fuel. It is a liquid at ordinary temperatures. When the liquid is burned, the reaction involved is chiefly 2CH3NO2(l)+32O2(g)2CO2(g)+N2(g)+3H2O(g) The standard enthalpy of formation of liquid nitromethaneat 25°C is 112kJmol1; other relevant values can be found in Appendix D. Calculate the enthalpy change in the burning of 1 molliquid nitromethane to form gaseous products at25°C. State explicitly whether the reaction is endothermicor exothermic. Would more or less heat be evolved if gaseous nitromethanewere burned under the same conditions?Indicate what additional information (if any) you would need to calculate the exact amount of heat, and show just how you would use this information.
Explain inyour own words why work done by the system is defined as the negative of pV, not positive pV.
What is the sign of the standard Gibbs free-energy change at low temperatures and at high temperatures for the formation of hydrogen sulfide from the elements? H2(g)+18S8(s)H2S(g)