Concept explainers
Interpretation:
The
Concept Introduction:
Hess’s Law: The total enthalpy change for a
Answer to Problem 102QRT
For Given Step 1, the value is
For Given Step 2, the value is
For Given Step 3, the value is
The standard reaction enthalpy value for net equation is
The overall reaction is endothermic.
Explanation of Solution
Given Step 1:
Using the above given reaction enthalpy is calculated by subtracting the summation of formation of products from the summation of formation enthalpy of reactants.
Given Step 2:
Using the above given reaction enthalpy is calculated by subtracting the summation of formation of products from the summation of formation enthalpy of reactants.
Given Step 3:
Using the above given reaction enthalpy is calculated by subtracting the summation of formation of products from the summation of formation enthalpy of reactants.
The above three expressions are added in order to obtain the net equation as follows,
Summation of the given equations and eliminating the reactants that show as products during summation are done. Then, the remaining reactant and products which form the net equation for the reaction and their individual reaction enthalpy changes values are added to get the net reaction enthalpy change value.
The obtained net equation value is positive hence, the reaction is endothermic.
Want to see more full solutions like this?
Chapter 4 Solutions
EBK CHEMISTRY: THE MOLECULAR SCIENCE
- Water gas, a mixture of carbon monoxide and hydrogen, is produced by treating carbon (in the form of coke or coal) with steam at high temperatures. (See Study Question 83.) C(s) + H2O(g) CO(g) + H2(g) Not all of the carbon available is converted to water gas since some is burned to provide the heat for the endothermic reaction of carbon and water. What mass of carbon must be burned (to CO2 gas) to provide the energy to convert 1.00 kg of carbon to water gas?arrow_forwardA rebreathing gas mask contains potassium superoxide, KO2, which reacts with moisture in the breath to give oxygen. 4KO2(s)+2H2O(l)4KOH(s)+3O2(g) Estimate the grams of potassium superoxide required to supply a persons oxygen needs for one hour. Assume a person requires 1.00 102 kcal of energy for this time period. Further assume that this energy can be equated to the heat of combustion of a quantity of glucose, C6H12O6, to CO2(g) and H2O(l). From the amount of glucose required to give 1.00 102 kcal of heat, calculate the amount of oxygen consumed and hence the amount of KO2 required. The ff0 for glucose(s) is 1273 kJ/mol.arrow_forwardOne of the components of polluted air is NO. It is formed in the high-temperature environment of internal combustion engines by the following reaction: N2(g)+O2(g)2NO(g)H=180KJ Why are high temperatures needed to convert N2 and O2 to NO?arrow_forward
- Insoluble AgCl(s) precipitates when solutions of AgNO3(aq) and NaCl(aq) are mixed. AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq) rH = ? To measure the energy evolved in this reaction, 250. mL of 0.16 M AgNO3(aq) and 125 mL of 0.32 M NaCl(aq) are mixed in a coffee-cup calorimeter. The temperature of the mixture rises from 21.15 C to 22.90 C. Calculate the enthalpy change for the precipitation of AgCl(s), in kJ/mol. (Assume the density of the solution is 1.0 g/mL and its specific heat capacity is 4.2 J/g K.)arrow_forwardNitromethane, CH3NO2, can be used as a fuel. When the liquid is burned, the (unbalanced) reaction is mainly CH3NO2(l) + O2(g) CO2(g) + N2(g) + H2O(g) a. The standard enthalpy change of reaction (Hvan ) for the balanced reaction (with lowest whole-number coefficients) is 1288.5 kJ. Calculate Hf0 for nitromethane. b. A 15.0-L flask containing a sample of nitromethane is filled with O2 and the flask is heated to 100.C. At this temperature, and after the reaction is complete, the total pressure of all the gases inside the flask is 950. torr. If the mole fraction of nitrogen (nitrogen) is 0.134 after the reaction is complete, what mass of nitrogen was produced?arrow_forwardxplain why aluminum cans make good storage containers for soft drinks. Styrofoam cups can be used to keep coffee hot and cola cold. How can this be?arrow_forward
- Nitrogen monoxide, a gas recently found to be involved in a wide range of biological processes, reacts with oxygen to give brown NO2 gas. 2 NO(g) + O2(g) NO2(g)rH = 114.1 kJ/mol-rxn Is this reaction endothermic or exothermic? What is the enthalpy change if 1.25 g of NO is converted completely to NO2?arrow_forwardThe equation for the fermentation of glucose to alcohol and carbon dioxide is: C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g) The enthalpy change for the reaction is 67 kJ. Is this reaction exothermic or endothermic? Is energy, in the form of heat, absorbed or evolved as the reaction occurs?arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
- Chemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningWorld of Chemistry, 3rd editionChemistryISBN:9781133109655Author:Steven S. Zumdahl, Susan L. Zumdahl, Donald J. DeCostePublisher:Brooks / Cole / Cengage LearningChemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage Learning