Concept explainers
Use Table 8.3 to obtain AHO for the following thermochemical equations:
(a)
(b)
(c)
(a)
Interpretation:
The value of ΔH° for the given chemical equation needs to be calculated.
Concept introduction:
The change in standard enthalpy for a reaction,
Where, np and nr are the number of moles of the products and reactants
Answer to Problem 43QAP
ΔH° = +58.9 kJ
Explanation of Solution
The given chemical equation is as follows:
The amount of heat absorbed or evolved can be given in terms of the enthalpy change for the above reaction. Based on equation (1):
Putting the values from table 8.3:
(b)
Interpretation:
The value of ΔH° for the given chemical equation needs to be calculated.
Concept introduction:
The change in standard enthalpy for a reaction,
Where, np and nr are the number of moles of the products and reactants.
Answer to Problem 43QAP
ΔH° = +108.5 kJ
Explanation of Solution
The given chemical equation is:
The amount of heat absorbed or evolved can be given in terms of the enthalpy change for the above reaction. Based on equation (1), we have:
Putting the values from table 8.3 thus,
(c)
Interpretation:
The value of ΔH° for the given chemical equation needs to be calculated.
Concept introduction:
The change in standard enthalpy for a reaction,
Where, np and nr are the number of moles of the products and reactants.
Answer to Problem 43QAP
ΔH° = -179.9 kJ
Explanation of Solution
The given chemical equation is:
The amount of heat absorbed or evolved can be given in terms of the enthalpy change for the above reaction. Based on equation (1), we have:
Putting the values from table 8.3:
Want to see more full solutions like this?
Chapter 8 Solutions
Chemistry: Principles and Reactions
- hat is the enthalpy change for a process? Is enthalpy a state function? In what experimental apparatus are enthalpy changes measured?arrow_forwardThe thermochemical equation for the burning of methane, the main component of natural gas, is CH4(g)+2O2(g)CO2(g)+2H2O(l)H=890kJ (a) Is this reaction endothermic or exothermic? (b) What quantities of reactants and products are assumed if H = 890 kJ? (c) What is the enthalpy change when 1.00 g methane burns in an excess of oxygen?arrow_forwardWith a platinum catalyst, ammonia will burn in oxygen to give nitric oxide, NO. 4NH3(g)+5O2(g)4NO(g)+6H2O(g);H=906kJ What is the enthalpy change for the following reaction? NO(g)+32H2O(g)NH3(g)+34O2(g)arrow_forward
- The reaction of quicklime, CaO, with water produces slaked lime, Ca(OH)2, which is widely used in the construction industry to make mortar and plaster. The reaction of quicklime and water is highly exothermic: (a) What is the enthalpy of reaction per gram of quicklime that reacts? (b) How much heat, in kilojoules, is associated with the production of 1 ton of slaked lime?arrow_forwardHydrazine, N2H4, is a colorless liquid used as a rocket fuel. What is the enthalpy change for the process in which hydrazine is formed from its elements? N2 (g) + 2H2 (g) → N2H4(1) Use the following reactions and enthalpy changes: N2H4 (1) + O2 (g) → N2 (g) + 2H,O(1); AH = -622.2 kJ H2 (g) + O2 (9) → H2O(1); AH = -285.8 kJ AH = kJ %3Darrow_forwardWrite a balanced equation for the formation of CO2(g) from C(s) and O2(g). Calculate the enthalpy change for this reaction using the following data (at 25 degrees Celsius): C(s) + 1/2 O2(g) --> CO(g) change in H = -111 kJ CO(g) + 1/2 O2(g) --> CO2(g) change in H = -394 kJ Is the reaction endothermic or exothermic?arrow_forward
- Using the standard enthalpies of formation (pictured), calculate ΔHº for the following reactions:a) CO2 (g) + 2NH3 (g) → H2O (g) + CO(NH2)2 (g) b) 2CH4 (g) + Cl2 (g) → 2 CH3Cl (g)arrow_forwardIf the enthalpy change for the reaction below is 46.72 kJ, how many grams of ammonia canbe produced if 50.7 kJ of heat energy are provided to the reaction? 4 NO + 6 H2O --> 4 NH3 + 5 O2arrow_forward(a) Consider the hypothetical element X. XO reacts with hydrogen gas to form XH;OH. Calculate the enthalpy of this reaction given that: (i) the enthalpy change that occurs when X reacts with oxygen gas to form XO is -221.0 kJ (ii) the enthalpy change that occurs when X reacts with oxygen gas and hydrogen gas to form XH,OH is -402.4 kJ. Calculate the distance between the centers of Y²* and Z² ions in a YZ lattice given that when 3.6 g of the compound are formed from its gaseous ions, 3.8 kJ of energy are released. The proportionality constant, k = 8.01 x 101" J pm. Molar mass of YZ: 257 g moľ' (b) (c) When a sample of vanadium metal absorbs 353 kJ of energy, the 'd' electrons of the metal atoms undergo a transition from their ground state to the fifth electron shell. Calculate the mass of this metal sample.arrow_forward
- Use heat of formation data from Appendix E to calculate ∆H ° for the following reaction:ClO2 (g) + O(g) → ClO(g) + O2(g)arrow_forwardWrite the chemical equation for the enthalpy of formation reaction for (NH4)2CO3 (s).arrow_forwardGiven the following ræactions and their enthalpies: ΔΗ (k/mol), +436 2H(g) H2(g) 0,(g) - 20(g) +495 H(g) + 02(g) Н.О(g) -242 (a) Devise a way to calculate AH for the reaction H,O(g) → 2H(g) + O(g) (b) From this, estimate the H-O bond energy.arrow_forward
- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage LearningIntroductory Chemistry: A FoundationChemistryISBN:9781337399425Author:Steven S. Zumdahl, Donald J. DeCostePublisher:Cengage Learning
- Chemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry by OpenStax (2015-05-04)ChemistryISBN:9781938168390Author:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark BlaserPublisher:OpenStax