Concept explainers
Hydrazine
Interpretation:
The balanced reaction, the enthalpy of formation, the enthalpy of reaction, for the given reaction is to be determined and the balanced reaction for burning of hydrazine and ammonia is to be written for each processes and their enthalpy of reaction is to be determined. The compound that causes more increase in temperature is to be identified.
Concept Introduction:
The standard enthalpy change for a reaction is the amount of enthalpy change that occurs at the standard conditions.
The standard enthalpy of reaction is to be determined using the equation as follows:
Here, the stoichiometric coefficients are represented by m for reactants and n for products and the enthalpies of formation at standard conditions are represented by
The standard enthalpy of formation is the amount of heat change when one mole of compound is formed from its integral elements that are present in their standard states.
The heat is related to the change in temperature of a material, which is as follows:
Here, q represents heat, s signifies specific heat, m shows mass, and
Answer to Problem 143AP
Solution:
a)
b) The reaction for hydrazine and oxygen is as follows:
and the reaction for ammonia and oxygen is as follows:
c)
The enthalpy of reaction of hydrazine with oxygen is
and for reaction of ammonia with oxygen is
d)
The heat is more for ammonia, so it will cause more increase in temperature.
Explanation of Solution
a) A balanced chemical equation for the given process.
The reaction for decomposition of hydrazine is as follows:
The balancing of a chemical reaction is done by the law of conservation of mass. According to this law, the mass of a species in the chemical reaction is conserved. It means that the mass of an atom on the reactant side is equal to that on the product side.
The reaction after balancing is given as follows:
b)
Standard enthalpy of formation of hydrazine is
The reaction for decomposition of hydrazine is as follows:
From appendix 2, the enthalpy of formation values is as follows:
The nitrogen gas is in its most stable form, so its enthalpy of formation is zero.
The standard enthalpy of reaction is calculated by the expression, which is as follows:
Now, the standard enthalpy of given reaction is calculated as follows:
Substitute
for
and
in the above equation.
Hence, the enthalpy of reaction is
c) Balance equations for the processes and
for the process.
The reaction of hydrazine with oxygen is as follows:
The reaction of ammonia with oxygen is as follows:
Now, the standard enthalpy of the given reaction is calculated as follows:
Now, the standard enthalpy of reaction of hydrazine with oxygen is given as follows:
Substitute
for
and
in the above equation.
Now, the standard enthalpy of reaction of ammonia with oxygen is given as follows:
Substitute
for
and
for
in the above equation.
Hence, the enthalpy of reaction of hydrazine with oxygen is
and for reaction of ammonia with oxygen is
d) Equal masses of hydrazine and ammonia burn in separate bomb calorimeter, the one which will cause the greater increase in temperature.
The heat is calculated by the expression, which is as follows:
For ammonia:
The molar mass is
The enthalpy is
The mass is
Substitute
for
and
for
For hydrazine:
The molar mass is
The enthalpy is
The mass is
Substitute
for
and
for
As the heat is more for ammonia, so it will cause more increase in temperature.
Want to see more full solutions like this?
Chapter 5 Solutions
Chemistry
Additional Science Textbook Solutions
Organic Chemistry
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
Chemistry: Atoms First
Organic Chemistry As a Second Language: Second Semester Topics
Organic Chemistry
- When lightning strikes, the energy can force atmospheric nitrogen and oxygen to react to make NO: N2(g)+O2(g)2NO(g)H=+181.8kJ (a) Is this reaction endothermic or exothermic? (b) What quantities of reactants and products are assumed if H = +181.8 kJ? (c) What is the enthalpy change when 3.50 g nitrogen is reacted with excess O2(g)?arrow_forwardThe 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: CaO(s)+H2O(l)Ca(OH)2(s)H=350kJmol1 (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_forwardCalcium carbide, CaC2, is manufactured by reducing lime with carbon at high temperature. (The carbide is used in turn to make acetylene, an industrially important organic chemical.) Is the reaction endothermic or exothermic?arrow_forward
- The 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_forwardThe enthalpy change for the following reaction is 393.5 kJ. C(s,graphite)+O2(g)CO2(g) (a) Is energy released from or absorbed by the system in this reaction? (b) What quantities of reactants and products are assumed? (c) Predict the enthalpy change observed when 3.00 g carbon burns in an excess of oxygen.arrow_forwardConsider the Haber process: N2(g)+3H2(g)2NH3(g);H=91.8kJ The density of ammonia at 25C and 1.00 atm is 0.696 g/L. The density of nitrogen, N2, is 1.145 g/L, and the molar heat capacity is 29.12 J/(mol C). (a) How much heat is evolved in the production of 1.00 L of ammonia at 25C and 1.00 atm? (b) What percentage of this heat is required to heat the nitrogen required for this reaction (0.500 L) from 25C to 400C, the temperature at which the Haber process is run?arrow_forward
- The first step in the preparation of lead from its ore (galena, PbS) consists of roasting the ore. PbS(s)+32O2(g)SO2(g)+PbO(s) Calculate the standard enthalpy change for this reaction, using enthalpies of formation (see Appendix C).arrow_forwardUse the appropriate tables to calculate H for (a) the reaction between copper(II) oxide and carbon monoxide to give copper metal and carbon dioxide. (b) the decomposition of one mole of methyl alcohol (CH3OH) to methane and oxygen gases.arrow_forwardAn industrial process for manufacturing sulfuric acid, H2SO4, uses hydrogen sulfide, H2S, from the purification of natural gas. In the first step of this process, the hydrogen sulfide is burned to obtain sulfur dioxide, SO2. 2H2S(g)+3O2(g)2H2O(l)+2SO2(g);H=1124kJ The density of sulfur dioxide at 25C and 1.00 atm is 2.62 g/L, and the molar heat capacity is 30.2 J/(mol C). (a) How much heat would be evolved in producing 1.00 L of SO2 at 25C and 1.00 atm? (b) Suppose heat from this reaction is used to heat 1.00 L of the SO2 from 25C to 500C for its use in the next step of the process. What percentage of the heat evolved is required for this?arrow_forward
- How much heat is produced by combustion of 125 g of methanol under standard state conditions?arrow_forwardOne step in the manufacturing of sulfuric acid is the conversion of SO2(g) to SO3(g). The thermochemical equation for this process is SO2(g)+12O2(g)SO3(g)H=98.9kJ The second step combines the SO3 with H2O to make H2SO4. (a) Calculate the enthalpy change that accompanies the reaction to make 1.00 kg SO3(g). (b) Is heat absorbed or released in this process?arrow_forwardAcetic acid, HC2H3O2, is the sour constituent of vinegar (acetum is Latin for vinegar). In an experiment, 3.58 g of acetic acid was burned. HC2H3O2(l)+2O2(g)2CO2(g)+2H2O(l) If 52.0 kJ of heat evolved, what is H per mole of acetic acid?arrow_forward
- General Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage LearningChemistry & 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 Learning
- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage Learning