When vinegar (CH3COOH) and baking soda (NaHCO3) are combined, the mixture spontaneously undergoes an endothermic reaction while releasing CO2 gas. Would the test tube feel hot or cold? Do you think this reaction would have a + or − value for ΔG? Explain your reasoning.
To determine:
If the test tube containing the given reaction mixture of vinegar and baking soda is hot or cold.
Introduction:
Thermodynamics is the branch of chemistry which studies the difference of heat and energies of product and reactant in the chemical reaction. Therefore, the sign of free energy change and heat change for a given chemical reaction is predicted by using the concept of thermodynamics.
Explanation of Solution
Endothermic reactions are the reactions in which heat is absorbed. In endothermic reactions, the flow of heat is inside the reaction mixture that results in a positive value of enthalpy change.
Exothermic reactions are the reactions which involve the release of heat. In exothermic reactions, the flow of heat is outside the reaction mixture that results in the negative value of enthalpy change.
A spontaneous process is a process which does not require any external effort for its initiation and a non-spontaneous process is a process which requires heat for its initiation.
As per the given facts, the temperature of the given test tube containing the reaction mixture depends upon the enthalpy change of the reaction. If enthalpy change of the reaction is positive, the test tube will be cold after the completion of the reaction and if the enthalpy change is negative, the test tube will be hot after the completion of the reaction.
Since the given reaction is given to be spontaneous and endothermic in nature; therefore, heat flows inside the reaction mixture and test tube containing the reaction mixture will be cold after the completion of the reaction.
To determine:
The sign of
Introduction:
The free energy change
Explanation of Solution
The free energy change
Since the stated reaction is given to be spontaneous in nature; therefore, the free energy change of the reaction is negative.
Want to see more full solutions like this?
Chapter 5 Solutions
GENERAL ORGANIC+BIOLOGICAL CHEM.(LOOSE)
- A beaker of water at 40C (on the left in the drawing) and a beaker of ice water at 0°C are placed side by side in an insulated container. After some time has passed, the temperature of the water in the beaker on the left is 30°C and the temperature of the ice water is still 0°C. Describe what is happening in each beaker (a) on the molecular level and (b) in terms of the second law of thermodynamicsarrow_forwardWrite the balanced chemical equation for the combustion of methane, CH4(g), to give carbon dioxide and water vapor. Explain why it is difficult to predict whether S is positive or negative for this chemical reaction.arrow_forwardThe molecular scale pictures below show snapshots of a strong acid at three different instants after it is added to water. Place the three pictures in the correct order so that they show the progress of the spontaneous process that takes place as the acid dissolves in the water. Explain your answer in terms of entropyarrow_forward
- Using the relevant S 298 values listed in Appendix G, calculate S 298 for the following changes: (a) N2(g)+3H2(g)2NH3(g) (b) N2(g)+52O2(g)N2O5(g)arrow_forwardNitrogen gas reacts with hydrogen gas to form ammonia gas .Consider the reaction between nitrogen and hydrogen as depicted below: a. Draw what the container will look like after the reaction has gone to completion. Assume a constant pressure of 1 atm. b. Is the sign of work positive or negative, or is the value of work equal to zero for the reaction? Explain your answer.arrow_forwardGiven the following data 2O3(g) 3O2(g)H = 427 kJ O2(g) 2O(g)H = 495 kJ NO(g) + O3(g) NO2(g) + O2(g)H = 199 kJ Calculate H for the reaction NO(g) + O(g) NO2(g)arrow_forward
- A piece of unknown solid substance weighs 437.2 g, and requires 8460 J to increase its temperature from 19.3 °C to 68.9 °C. (a) What is the specific heat of the substance? (b) If it is one of the substances found in Table 5.1, what is its likely identity?arrow_forwardPredict the sign of S and then calculate S for each of the following reactions. a. H2(g) + 12O2(g) H2O(l) b. 2CH3OH(g) + 3O2(g) 2CO2(g) + 4H2O(g) c. HCl(g) H+(aq) + Cl (aq)arrow_forwardIdentify the following processes as either spontaneous or not spontaneous. (a) Liquid water turns to ice when placed in a freezer at 5 C. (b) Nitrogen gas is compressed to one half its original volume. (c) Sodium reacts with water forming H2(g) and NaOH(aq). (d) Slightly soluble CaSO4 [Ksp = 4.5 105) dissolves in water to form a saturated solution.arrow_forward
- 9.96 Most first aid "cold packs" are based on the endothermic dissolution of ammonium nitrate in water: NH4NO3(s)NH4+(aq)+NO3(aq) H= 25.69 kJ A particular cold pack contains 50.0 g of NH4NO3 and 125.0 g of water. When the pack is squeezed, the NH4NO3dissolves in the water. If the pack and its contents are initially at 24.0°C, what is the lowest temperature that this bag could reach? (Assume that the ammonium nitrate solution has a specific heat of 4.25J g-l K-l, and that the heat capacity of the bag itself is small enough to be neglected.)arrow_forwardHow many L atm are equal to 12.2 kJ of work?arrow_forwardThe decomposition of ozone, O3, to oxygen, O2, is an exothermic reaction. What is the sign of q? If you were to touch a flask in which ozone is decomposing to oxygen, would you expect the flask to feel warm or cool?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 LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage Learning
- Chemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage Learning