Videos
Consider exercise 2.5. Would the work be more or less if it were performed against different external pressures found (a) at the top of Mount Everest, (b) at the bottom of Death Valley, (c) in space?
(a)
Interpretation:
Predict whether the work will be more or less when it is performed at the top of the Mount Everest.
Concept introduction:
The work is performed on an object when an object moves a certain distance s due to the force F. Mathematically, it is indicated by the dot product of the force vector F and the distance vector s. The mathematical equation is given below,
Where Ѳ is the angle between the vectors F and s. The unit of work is joules. Work is a way to transfer the energy. The energy is defined as the ability to do work and so energy and work are described using the same unit in joules.
Answer to Problem 2.6E
The work would be less because the external pressure is less.
Explanation of Solution
Gases do expansion or compression work by following the equation.
The given statement is like a person lifting a book or any other material from ground state to higher state does work against the gravity.
The gases can do the work through expansion or compression against the constant external pressure. Thus when the gas does the work in a piston and move it against the external pressure. Then the volume increase and so the work is negative as the external pressure is less.
Thus the work would be less because the external pressure is less.
(b)
Interpretation:
Predict whether the work will be more or less when it is performed at the bottom of the Death valley.
Concept introduction:
The work is performed on an object when an object moves a certain distance s due to the force F. Mathematically, it is indicated by the dot product of the force vector F and the distance vector s. The mathematical equation is given below,
Where Ѳ is the angle between the vectors F and s. The unit of work is joules. Work is a way to transfer the energy. The energy is defined as the ability to do work and so energy and work are described using the same unit in joules.
Answer to Problem 2.6E
The work would be more because the external pressure is more.
Explanation of Solution
Gases do expansion or compression work by following the equation.
The given statement is like a person lifting a book or any other material from ground state to same state does work with the gravity.
The gases can do the work through expansion or compression against the constant external pressure. Thus when the gas does the work in a piston and move it with the external pressure. Then the volume decrease and so the work is positive as the external pressure is more.
Thus the work would be more because the external pressure is more.
(c)
Interpretation:
Predict whether the work will be more or less when it is performed at space.
Concept introduction:
The work is performed on an object when an object moves a certain distance s due to the force F. Mathematically, it is indicated by the dot product of the force vector F and the distance vector s. The mathematical equation is given below,
Where Ѳ is the angle between the vectors F and s. The unit of work is joules. Work is a way to transfer the energy. The energy is defined as the ability to do work and so energy and work are described using the same unit in joules.
Answer to Problem 2.6E
No work would be performed because the external pressure is zero.
Explanation of Solution
Gases do expansion or compression work by following the equation.
Considering the expansion of a gas into a larger volume, which is an initially a vacuum. In this, the gas is expanding against a Pext of 0, where the work done by the gas is equals to zero. Such a process is called a free expansion. Hence, work = 0 for free expansion.
Thus no work would be performed because the external pressure is zero.
Want to see more full solutions like this?
Chapter 2 Solutions
Bundle: Physical Chemistry, 2nd + Student Solutions Manual
- In an electrolytic cell, indicate the formula that relates E0 to the temperature T.arrow_forward-- 14:33 A Candidate Identification docs.google.com 11. Compound A can transform into compound B through an organic reaction. From the structures below, mark the correct one: HO A تھے۔ די HO B ○ A) Compounds A and B are isomers. B) Both have the same number of chiral carbons. C) Compound A underwent an addition reaction of Cl2 and H2O to form compound B. D) Compound A underwent a substitution reaction forming the intermediate chlorohydrin to obtain compound B. E) Compound A underwent an addition reaction of Cl2 forming the chloronium ion and then added methanol to obtain compound B. 60arrow_forward-- 14:40 A Candidate Identification docs.google.com 13. The compound 1-bromo-hex-2-ene reacts with methanol to form two products. About this reaction, mark the correct statement: OCH3 CH3OH Br OCH3 + + HBr A B A) The two products formed will have the same percentage of formation. B) Product B will be formed by SN1 substitution reaction with the formation of an allylic carbocation. C) Product A will be formed by SN1 substitution reaction with the formation of a more stable carbocation than product B. D) Product A will be formed by an SN2 substitution reaction occurring in two stages, the first with slow kinetics and the second with fast kinetics. E) The two compounds were obtained by addition reaction, with compound B having the highest percentage of formation. 57arrow_forward
- -- ☑ 14:30 A Candidate Identification docs.google.com 10. Amoxicillin (figure X) is one of the most widely used antibiotics in the penicillin family. The discovery and synthesis of these antibiotics in the 20th century made the treatment of infections that were previously fatal routine. About amoxicillin, mark the correct one: HO NH2 H S -N. HO Figura X. Amoxicilina A) It has the organic functions amide, ester, phenol and amine. B) It has four chiral carbons and 8 stereoisomers. C) The substitution of the aromatic ring is of the ortho-meta type. D) If amoxicillin reacts with an alcohol it can form an ester. E) The structure has two tertiary amides. 62arrow_forwardThe environmental police of a Brazilian state received a report of contamination of a river by inorganic arsenic, due to the excessive use of pesticides on a plantation on the riverbanks. Arsenic (As) is extremely toxic in its many forms and oxidation states. In nature, especially in groundwater, it is found in the form of arsenate (AsO ₄ ³ ⁻ ), which can be electrochemically reduced to As ⁰ and collected at the cathode of a coulometric cell. In this case, Potentiostatic Coulometry (at 25°C) was performed in an alkaline medium (pH = 7.5 throughout the analysis) to quantify the species. What potential (E) should have been selected/applied to perform the analysis, considering that this is an exhaustive electrolysis technique (until 99.99% of all AsO ₄ ³ ⁻ has been reduced to As ⁰ at the electrode, or n( final) = 0.01% n( initial )) and that the concentration of AsO ₄ ³ ⁻ found in the initial sample was 0.15 mmol/L ? Data: AsO ₄ 3 ⁻ (aq) + 2 H ₂ O ( l ) + 2 e ⁻ → A s O ₂ ⁻ ( a…arrow_forward-- 14:17 15. Water-soluble proteins are denatured when there is a change in the pH of the environment in which they are found. This occurs due to the protonation and deprotonation of functional groups present in their structure. Choose the option that indicates the chemical bonds modified by pH in the protein represented in the following figure. E CH2 C-OH CH2 H₂C H₁C CH CH3 CH3 CH CH₂-S-S-CH₂- 910 H B -CH2-CH2-CH2-CH₂-NH3* −0—C—CH₂- ○ A) A, C e D. • В) Вес ○ C) DeE ○ D) B, De E ○ E) A, B e C 68arrow_forward
- Suppose sodium sulfate has been gradually added to 100 mL of a solution containing calcium ions and strontium ions, both at 0.15 mol/L. Indicate the alternative that presents the percentage of strontium ions that will have precipitated when the calcium sulfate begins to precipitate. Data: Kps of calcium sulfate: 2.4x10 ⁻ ⁵; Kps of strontium sulfate: 3.2x10 ⁻ ⁷ A) 20,2 % B) 36,6 % C) 62,9 % D) 87,5 % E) 98.7%arrow_forward14:43 A Candidate Identification docs.google.com 14. The following diagrams represent hypothetical membrane structures with their components numbered from 1 to 6. Based on the figures and your knowledge of biological membranes, select the correct alternative. | 3 5 || 人 2 500000 6 A) Structures 1, 3, 5, 2 and 4 are present in a constantly fluid arrangement that allows the selectivity of the movement ○ of molecules. Structure 4, present integrally or peripherally, is responsible for this selection, while the quantity of 6 regulates the fluidity. B) The membranes isolate the cell from the environment, but allow the passage of water-soluble molecules thanks to the presence of 2 and 3. The membrane in scheme is more fluid than that in 55arrow_forward12. Mark the correct statement about reactions a and b : a. Br + -OH Br b. + Br H₂O + Br -OH + H₂O A) The reactions are elimination reactions, with reaction "a" being of type E2 and reaction "b" being of type E1. B) Reaction "a" is an E2 type elimination occurring in one step and reaction "b" is an SN1 type substitution. C) Both reactions can result in the formation of carbocation, but in reaction "b" the most stable carbocation will be formed. D) Both reactions occur at the same rate ○ and have the same number of reaction steps. E) Reaction "b" is an E2 type elimination occurring in two steps and reaction "a" is an SN2 type substitution.arrow_forward
- Chloroform, long used as an anesthetic and now considered carcinogenic, has a heat of vaporization of 31.4 kJ/mol. During vaporization, its entropy increases by 94.2 J/mol.K. Therefore, select the alternative that indicates the temperature, in degrees Celsius, at which chloroform begins to boil under a pressure of 1 atm. A) 28 B) 40 C) 52 D) 60 E) 72arrow_forwardIf we assume a system with an anodic overpotential, the variation of n as a function of current density: 1. at low fields is linear 2. at higher fields, it follows Tafel's law Obtain the range of current densities for which the overpotential has the same value when calculated for 1 and 2 cases (maximum relative difference of 5% compared to the behavior for higher fields). To which overpotential range does this correspond? Data: i = 1.5 mA cm², T = 300°C, B = 0.64, R = 8.314 J K1 mol-1 and F = 96485 C mol-1.arrow_forwardAnswer by equation pleasearrow_forward
Physical ChemistryChemistryISBN:9781133958437Author:Ball, David W. (david Warren), BAER, TomasPublisher:Wadsworth Cengage Learning,
Chemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage Learning
Chemistry for Engineering StudentsChemistryISBN:9781337398909Author:Lawrence S. Brown, Tom HolmePublisher:Cengage Learning
ChemistryChemistryISBN: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