Concept explainers
Liquids A (molar mass 100 g/mol) and B (molar mass 110 g/mol) form an ideal solution. At 55°C, A has a vapor pressure of 95 mmHg and B has a vapor pressure of 42 mmHg. A solution is prepared by mixing equal masses of A and B. (a) Calculate the mole fraction of each component in the solution. (b) Calculate the partial pressures of A and B over the solution at 55°C. (c) Suppose that some of the vapor described in (b) is condensed to a liquid in a separate container. Calculate the mole fraction of each component in this liquid and the vapor pressure of each component above this liquid at 55°C.
(a)

Interpretation:
Mole fraction of each component present in the given solution has to be calculated.
Concept introduction:
Raoult’s law states that in an ideal mixture of liquid solution, partial pressure of every component is equal to its mole fraction multiplied into vapour pressure of its pure components.
Where,
Mole fraction: Concentration of the solution can also expressed by mole fraction. Mole fraction is equal to moles of the component divided by total moles of the mixture.
Answer to Problem 12.130QP
Mole fraction of component A is
Mole fraction of component B is
Explanation of Solution
Given data:
Molar mass of liquid A =
Molar mass of liquid B =
Vapour pressure of A =
Vapour pressure of B =
Calculate mole fraction of each component:
Assume
The mole fraction of the component is calculated by moles of the component divided by the total number of moles in the mixture.
Substituting the values of moles of each component and total moles of the component, the mole fraction of each component has calculated.
(b)

Interpretation:
The partial pressure of the components over the given solution at
Concept introduction:
Raoult’s law states that in an ideal mixture of liquid solution, partial pressure of every component is equal to its mole fraction multiplied into vapour pressure of its pure components.
Where,
Answer to Problem 12.130QP
Partial pressure of solution A is
Partial pressure of solution B is
Explanation of Solution
Calculate partial pressure of each component:
The formula for partial pressure,
According to Raoult’s law, the vapour pressure of the solution is sum of the individual partial pressure exerted by the solution and then using partial pressure equation, partial pressure of each component has been calculated.
(c)

Interpretation:
The mole fraction of each component in the condensed liquid and the vapour pressure of the components above the condensed liquid at
Concept introduction:
Raoult’s law states that in an ideal mixture of liquid solution, partial pressure of every component is equal to its mole fraction multiplied into vapour pressure of its pure components.
Where,
Answer to Problem 12.130QP
Mole fraction of component A in condensed liquid is
Mole fraction of component B in condensed liquid is
Partial pressure of the component A above condensed liquid at
Partial pressure of the component B above condensed liquid at
Explanation of Solution
The mole fraction is equal to partial pressure of the component divided by the total pressure.
Substituting the value of partial pressure of each component and total pressure, the mole fraction of each component at condensed liquid has calculated.
Calculation of partial pressure of each component
The mole fraction of each component in condensed liquid is,
Want to see more full solutions like this?
Chapter 12 Solutions
CHEMISTRY-ALEKS 360 ACCESS
- If I have 10 data points for variables x and y, when I represent y versus x I obtain a line with the equation y = mx + b. Is the slope m equal to dy/dx?arrow_forwardThe data for the potential difference of a battery and its temperature are given in the table. Calculate the entropy change in J mol-1 K-1 (indicate the formulas used).Data: F = 96485 C mol-1arrow_forwardIn a cell, the change in entropy (AS) can be calculated from the slope of the E° vs 1/T graph. The slope is equal to -AS/R, where R is the gas constant. Is this correct?arrow_forward
- Using the Arrhenius equation, it is possible to establish the relationship between the rate constant (k) of a chemical reaction and the temperature (T), in Kelvin (K), the universal gas constant (R), the pre-exponential factor (A) and the activation energy (Ea). This equation is widely applied in studies of chemical kinetics, and is also widely used to determine the activation energy of reactions. In this context, the following graph shows the variation of the rate constant with the inverse of the absolute temperature, for a given chemical reaction that obeys the Arrhenius equation. Based on the analysis of this graph and the concepts acquired about the kinetics of chemical reactions, analyze the following statements: I. The activation energy (Ea) varies with the temperature of the system. II. The activation energy (Ea) varies with the concentration of the reactants. III. The rate constant (K) varies proportionally with temperature. IV. The value of the…arrow_forwardIn 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_forwardSuppose 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_forward
- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher: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 LearningGeneral, Organic, and Biological ChemistryChemistryISBN:9781285853918Author:H. Stephen StokerPublisher:Cengage LearningChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage Learning





