The vapor pressure of methanol is 92 torr when pure at that temperature. ), A sample of O_2 gas was collected over water at 23 degrees C and 711 torr. We also use third-party cookies that help us analyze and understand how you use this website. Consider gaseous water at 300 K at a pressure of 10.0 Torr. Calculate the pressure of the m. One liter of a gas mixture at 0 degrees Celsius and 108.26 kPa contains 250 mg/L of H2S gas. At a given temperature, pure A has a vapor pressure of 140 torr and pure B has a vapor pressure of 60 torr. A sample of oxygen gas is saturated with water vapor at 27 C. The total pressure of the mixture is 814 torr, and the vapor pressure of water is 26.9 torr at 27 C. What is the partial pressure of, A gaseous mixture contains 2.00 grams of H2(g) and 8.00 grams of N2(g) at a temperature of 0.00 degrees Celsius. C2H5OH, is 44 torr at the same temperature. Which substance has the highest vapor pressure at room temperature? Not included: Methyl Isoamyl Ketone Petroleum Ether Propylene Carbonate Trifluoroacetic Acid A certain liquid has a vapor pressure of 92.0 torr at 23.0 degrees Celsius and 266.0 torr at 45.0 degrees Celsius. Thermophysical properties for temperatures ranging -50-150 oC are indicated in the table below. (Given: R = 8.314 J/molK). Calculate the value of Delta Hvap for this liquid. What is the partial pressure of O_2 collected over water at 25 degree C and 630 torr ? ), A mixture of 0.2 mole of alcohol of A and 0.5 mole of alcohol B has a total vapour pressure of 40 mmHg at 298 K. If the mixture obeys Raoult's law, find the pure vapour pressure of B at 298 K given th. (e) More information is needed. At 20 C, the vapour pressure of pure ethanol is 32.1 torr and Cookies are only used in the browser to improve user experience. At 50 degrees Celsius, the vapor pressures for methanol and ethanol are 406 and 222 torr, At 25 degrees Celsius, the vapor pressure of ethanol is 45 torr when pure. What is the vapor pressure of the solution prepared by dissolving 0.500 mol of biphenyl, C_12H_10 in 4.50 mol C_6H_6? The vapor pressure of pure water at 70^{\circ}C is 233.7 torr? Substance A mixture of three gases has a total pressure of 638 mmHg. Calculate the partial pressure, Between 20 and 80 degrees Celsius, the enthalpy of vaporization of benzene is 31.0 kJ/mol. 31 torrs b. Why ethanol has the higher vapor pressure than methanol? The lower flammability limit of methanol in air is 6 mole %. behaviour what is the vapour pressure (in torr) at 20 C of a \chi_{C_2H_5OH} = 1- 0.588 The vapor pressure of water is 289 torr at the same Calculate the ideal partial pressure of water at this temperature for a mixture of 45.0 g H_2O and 55.0 g CH_3OH? The Delta Hvap for ethanol is 39.3 kJ/mol. The vapor pressures of pure liquid A and pure liquid B are 45.9 torr and 99.2 torr, respectively. Correct answers: 2 question: The normal boiling point of methanol is 64.7C. the vapor pressure of. Partial pressure of O_2. Assume ideal behavior and calculate the partial pressures of ethanol and 1-propan, calculate the total vapour pressure of mixture of methanol(64g) and ethanol(92g) at 298K given that the pure vapour pressure of methanol is 90mmHg and ethanol is 45mmHg (C=12, H=1, O=16), A mixture of 0.2 moles of alcohol A and 0.5 moles of alcohol B has a total vapor pressure of 40 mmHg at 297 K. If the mixture obeys Raoult's law, find the vapor pressure of pure B at 297 K given that, The vapor pressure of ethanol is 100 mmHg at 34.9 degrees C. What is its vapor pressure at 65.5 degrees C? Assuming ideal behavior, what is the vapor pressure of a solution that contains twice as m. Calculate the partial pressure (in atm) of propane in a mixture that contains equal weights of propane (C_3H_8) and butane (C_4H_{10}) at 18 degree C and 746 mmHg. [MeNC(Me)C(H)C(Me)NMe] has made it potentially redoxactive, i.e. A 0.24 B 0.25 C 0.26 D 0.27 Hard Solution Verified by Toppr Correct option is A) According to Raoult's law, p=p 0x p = partial vapour pressure of methanol Coins can be redeemed for fabulous At 20.0C, the vapor pressure of ethanol is 45.0 torr, and the vapor pressure of methanol is 92.0 torr. Round each of your answers to 3 significant digits. copyright 2003-2023 Homework.Study.com. gifts. If the container is closed and the methanol reaches equilibrium with its vapor, what mass (in grams) of liquid methanol remain? So let's break this down. propanol are 303 and 44.6 torr, respectively. 72 g b. If R= 0.0821 liter-atmosphere/moles-degree K, the flask volume is 275 mL, the pressure is 775 Torr. The vapor pressure of mercury at 25 degrees C is 0.00243 atm. Calculate the partial pressure of He in the mixture (in atm). Hence, the total pressure above a solution is 73.4 torr. Vapor pressure of Methanol = {eq}\rm P^o_{CH_3OH} = 406\ torr Hv of a certain liquid is 24.0 kJ/mol. P_T = 272.02\ torr + 73.26\ torr\\ 35 P ethanol = 58 torr. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. The vapor pressure of a liquid is defined as the pressure exerted by the molecules that escapes from the liquid to form a separate vapor phase above the liquid surface. The vapor pressure of water at 100.0 degrees C is: (a) 175 torr. 5 I 5. In web metrics, which of the following best describes depth of The vapor pressure of methanol is 92 torr when pure at that temperature. What would be the new vapor pressure? The vapor pressure of water at 25 deg C is 23.8 mmHg. Just clear tips and lifehacks for every day. (Negative value should be indicated by kid walks around the perimeter of a wheat field in 60 min. 1 What is the vapor pressure of methanol and ethanol? The partial pressure of the O2 is 78.00 torr. Estimate the heat of vaporization of water if the vapor pressure is 17.54 torr at 20^(o) C and 149.4 torr at 60^(o) C. At 35C water has a vapor pressure of 42.2 torr. The vapor pressure of the resulting solution is \\ a) 123 torr b) 94.2 torr c) 65.8 torr d) 61.3 torr e) none. {/eq}. The pressure exerted by the vapor phase is called the vapor or saturation pressure Vapor or saturation pressure depends on temperature. Calculate the value of \Delta H_{vap} for this liquid. The vapor pressures of pure liquid A and pure liquid B are 45.9 torr and 99.2 torr, respectively. Determine the mass of glucose(molar mass =180g/mol) needed to add to 500g water to change the vapor pressure to 23.1 torr. What liquid has the highest vapor pressure? Calculate the total vapor pressure of a solution made by mixing Vapor pressure of pure ethanol and pure methanol at 20 C is 44.5 and 88.7 mmHg, respectively. b. The vapor pressure of liquid methanol, CH3OH, is 100. mm Hg at 294 K. A sample of CH3OH is placed in a closed, evacuated 572 mL container at a temperature of 294 K. It is found that all of the CH3OH i. Calculate the partial pressure exerted by the gas. P tot = P a + P b The partial pressures, P a and P b, are determined using Raoult's Law. \boxed{\rm P_{CH_3OH} = 272.02\ torr} The vapor pressure for methanol and ethanol at 50 C is 406 and 222 Torr, respectively. torr. 5 Does methanol have a high vapor pressure? x_{CH_3OH} = 0.67 Calculate the total vapor pressure above a solution of 32.4 g of methanol and 23.9 g of ethanol. Explain. What this means to you is: You will be handling dangerous concentrations of HCL and potentially generating a very nasty gas called Nitrous Dioxide. Calculate the vapor pressure in kPa. What is the vapor pressure of a 6.6% by mass aq ethylene glycol (HOC2H4OH) solution at 0oC? mol1. The enthalpy of vaporization of methanol is 35.27 kJ mol-1 at its boiling point of 64.1C. The vapor pressure of pure water at 50.0 ^oC is 92.5 mmHg. A certain liquid has a vapor pressure of 92.0 Torr at 23.0 degrees Celsius and 250.0 Torr at 45.0 degrees Celsius. Last Post; Feb 28, 2021; Replies 2 Views 679. Vapor pressure is the pressure exerted by the vapor molecules of a substance in a closed system. The vapor pressures of pure liquid A and pure liquid B are 45.9 torr and 99.2 torr, respectively. Find it in kJ/mol. The vapor pressure of pure benzene and toluene at, At a certain temperature the vapor pressure of pure benzene is measured to be 322 torr . A certain liquid has a vapor pressure of 92.0 Torr at 23.0 degrees Celsius and 250.0 Torr at 45.0 degrees Celsius. 1. AddThis use cookies for handling links to social media. A bowl is filled with water at a temperature of 20.0^{\circ}C and with a vapor pressure of 17.5 torr. What is the freezing point of a solution of dibromobenzene, \({{\bf{C}}_{\bf{6}}}{{\bf{H}}_{\bf{4}}}{\bf{B}}{{\bf{r}}_{\bf{2}}}\), in 0.250 kg of benzene, if the solution boils at 83.5 C? Calculate the Raoult s law reference activity coefficients for benzene and methanol in this solution. (b) Ethanol and methanol form a solution that behaves like an ideal . What is the mole fra. 45.3 g Mole fraction of propanol =. {eq}\rm P_{total} = P_1 + P_2 + P_3 ----- ), Methyl salicylate, C8H8O3, the odorous constituent of oil of wintergreen, has a vapor pressure of 1.00 torr at 54.3 degrees C and 10.0 torr at 95.3 degrees C. A. What is the vapor pressure of a 6.6% by mass aq ethylene glycol (HOC2H4OH) solution at 0oC? Calculate the vapor pressure of benzene at 26 degrees Celsius. Calculate its vapor pressure at 275.7 K. Calculate the vapor pressure of ethanol and the vapor pressure of water at 62.5 ^oC. What is the vapor pressure of ethanol under these conditions? Contact China Trader Jinan Tochem Co., Ltd for the product Methanol. The vapor pressure of ethanol is 100 mmHg at 34.9 degrees Celsius. (b) Ethanol and methanol form a solution that behaves like an ideal solution. So, for example, methanol has a vapor pressure of 94 torr at 25 C, and ethanol has a vapor pressure of 44 torr at 25 C. Determine the vapor pressure of a solution composed of 1.00 mol of liquid A and 3.00 mol of liquid B. Assuming ideal Click hereto get an answer to your question The vapour pressures of ethanol and methanol are 44.5 mm and 88.7 mm Hg respectively. vapor pressure of methanol at 20{eq}\rm ^\circ C 2.87 C. 3.87 D. 4.87 E. 5.87, The vapor pressure of pure benzene, C_6H_6 at 20^o C is 75mm Hg while the vapor pressure of toluene, C_7H_8 at this temperature is 22 mm Hg. 166.6 It increases with temperature. The vapor pressure of water at 25 degree C is 23.8 torr. For more data or any further information please search the DDB or contact DDBST. Answer in units of torr. The basic fabrication technique includes low-pressure chemical vapor deposited SnO 2 , chemical-bath deposited CdS, close-spaced sublimated CdTe, solution-CdCl 2 treatment, and an acid-contact. {/eq}, Moles of methanol = {eq}\rm n_{CH_3OH} = 0.2\ mol All rights reserved. 4) A mixture of 90.0 grams of CH4 and 10.0 grams of argon has a pressure of 250 torr under conditions of constant temperature and volume. You also have the option to opt-out of these cookies. At 45 degrees Celsius, the vapor pressure of benzene is 211 torr. Assume the density of the mixture is the same as that of the solvent. Calculate the vapor pressure of water at 25.0 o C . At this temperature, a solution is made in which the mole fractions of A and B are equal. Therefore viscosity, surface tension and density will decrease and vapor . (Vapour pressure of H_2O at 25 degree C is 23.8 torr). Solution: 1) 18.2 % means this: 18.2 g solute in 100 g of solution. Plot a vapor pressure curve for C2H4F2 from the following vapor pressures. CEquimolar gives a mole fraction of 0.5. What is the mole fraction in the vapor? A mixture of benzene and acetone has a vapor pressure of 196 torr at room temperature (25 degrees Celsius). If not, what can you say about the relative strengths of the solute-solvent interactions compared to the . Round your answer to 3 significant digits. The pressure inside the container is due to both liquids evaporating. Ist in einem offenen System der Dampfdruck einer Flssigkeit gleich dem Umgebungsdruck, so beginnt die . What is the partial pressure of the O_2 ? What is the partial pressure of the O_2? The number of moles of each substance is proportional to pressure, so the mole fraction of each component in the vapor can be calculated as follows: \(\begin{aligned}{\rm{C}}{{\rm{H}}_{\rm{3}}}{\rm{OH}} &= \;\dfrac{{{\rm{55}}}}{{\left( {{\rm{55 + 18}}} \right)}}\\{\rm{C}}{{\rm{H}}_{\rm{3}}}{\rm{OH}} &= \;{\rm{0}}{\rm{.78}}\\{{\rm{C}}_{\rm{2}}}{{\rm{H}}_{\rm{5}}}{\rm{OH}}\;&= \;\dfrac{{{\rm{18}}}}{{\left( {{\rm{55 + 18}}} \right)}}\\{{\rm{C}}_{\rm{2}}}{{\rm{H}}_{\rm{5}}}{\rm{OH}} &= \;{\rm{0}}{\rm{.25}}\end{aligned}\). (Given: R = 8.314 J/molK), A sample of O2(g) is saturated with water vapor at 27 degrees C. The total pressure of the mixture is 772 torr, and the vapor pressure of water is 26.7 torr at 27 degrees C. What is the partial pressu, At 25 degrees Celsius the vapor pressure of pure pentane is 511 torr and that of hexane is 150 torr. The vapor pressure of methanol, CH3OH, is 94 torr at 20 C. The vapor pressure of ethanol, C2H5OH, is 44 torr at the same temperature. {/eq}, Mole fraction of ethanol is calculated as-, {eq}\rm \chi_{C_2H_5OH} = 1 - \chi_{CH_3OH} Calculate the vapor pressure in atm and torr. Calculate the vapor pressure in atm and torr. What is the vapor pressure in atm and torr? The vapor pressure of dry ice (solid CO_2) is 672.2 torr at -80 degree C and 1486 torr at -70 degree C. (a) Calculate the molar heat of sublimation of CO_2. its vapor pressure by 10.0 torr at 35 degree C. The vapor pressure Assuming ideal behavior, what is the vapor pressure of a solution that contains twice as m, Equal moles of pure liquid benzene (vapor pressure of 94.2 torr) and pure liquid toluene (vapor pressure of 28.4 torr) are mixed together. 65. . {/eq}, Next, we know the Dalton's Law of partial pressure is given as-, {eq}\rm P_{total} = P^\circ_{CH_3OH} . National Center for Biotechnology Information. What is the vapor pressure at 17 degree celsius? 100 torr c. 47.6 to, A mixture of 0.2mole of alcohol A and 0.5mole of alcohol has a total vapor pressure of 40mmHg at 298k, if the mixture obeys Raoult's law, find the pure pressure of B at 298k given that the pressure of. If I collect a gas over this water, and the total gas pressure of the gas solution is found to be 277.9 torr, what would be the pressure of the pure gas? ), A sample of O_2 gas was collected over water at 23 degrees C and 711 torr. temperature. Supersaturated solutions of most solids in water are prepared by cooling saturated solutions. Vapor pressure is a liquid property related to evaporation. Plot a vapor pressure curve for Cl2O7 from the following vapor pressures. 35 = 0. Octane has a vapor pressure of 40 torr at 45.1 degrees Celsius and 400 torr at 104 degrees Celsius. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. What is the mole fraction in the vapor? Hf (kJ/mol) 48. At this temperature, a solution is made where the mole fractions of A and B are equal. Use this information to estimate the enthalpy of vaporization for ethanol. A substance has a vapor pressure of 77.86 mmHg at 318.3 K and a vapor pressure of 161.3 mmHg at 340.7 K. Calculate its heat of vaporization in kJ/mol. What is the total vapor pressure of the ideal solution made up in the following concentrations? The vapor pressure of methanol (CHOH) at 25.0C is 127.2 torr. At 40 C, heptane has a vapor pressure of about 92.0 torr and octane has a vapor pressure of about 31.2 torr. At that temperature, the vapor pressure of benzene and acetone are 0.125 atm and 230 torr, respectively. Calculate the partial pressure of each gas, the total pressure, and the composition of the mixture in mole percent. A. At 20 oC, Po for ether = 440 torr, Po for ethanol = 332 The vapor pressure of methanol {eq}\displaystyle Calculate the geometric mean return for the following data set: user contributions licensed under cc by-sa 4.0, Given that The vapoo pressuree of methanol (32.043 g/mol) CH_3OH is 94 toor at 20 degree c The vapor pressuree at ethanol(46.07 g/mol) C_2H_5OH is 44 toor at the same temperature now to calculate the total vapor pressuree above a solution of 32.4g of methanol and 23.9g of ethanol according to the dalton's law of partial pressuree. is 94 torr at 20 C. The Delta Hvap of water is 40.7 kJ/mol. However, ethanol is capable of hydrogen bonding and, therefore, exhibits stronger overall IMFs, which means that fewer molecules escape from the liquid at any given temperature, and so ethanol has a lower vapor pressure than diethyl ether. Vapor Pressure Burdick & Jackson solvents are arranged in order of increasing vapor pressure, the pressure exerted when the liquid phase of the solvent is in equilibrium with its vapor phase (at 20C unless otherwise indicated). It occurs at equilibrium, i.e., when the molecules are both vaporizing and condensing at the same rate at a particular pressure. methanol and 23.9 g of ethanol. What is the mole fraction of pentane in a pentane-hexane solution that has a vapor pressure of 302 torr at 25 degrees Celsius? What is the vapor pressure, at 28.0 degrees Celsius, of a solution made by mixing 0.250 moles of carbon disulfide and 0. Now, we will find the partial pressure of the liquids as follows: {eq}\rm P_{CH_3OH} = x_{CH_3OH}P^o_{CH_3OH} \\ At 40C, the vapor pressures of pure methanol and pure The vapor pressure of pure bromine at 300 K is 30.5 kPa, and the vapor pressure of CCl4 is 16.5 kPa. State any approximations made. What is the mole fraction of CH 3 OH in a solution in which the (partial) vapor pressure of CH 3 OH is 23.0 torr at 25 o C? Calculate the temperature at which a saturated methanol-air mixture at 1 atm would have a composition corresponding to the LFL. At 40C, heptane has a vapor pressure of about 92.2 torr and octane has a vapor pressure of about 31.2 torr. Methanol, CH3OH (32.04 g/mol) has a melting point equal to 176 K and a boiling point equal to 338 K. Using the thermodynamic data below, , in 0.250 kg of benzene, if the solution boils at 83.5 C. What is the thermal conductivity of methanol? The vapor pressure of ethanol, C 2 H 5 O H , is 44 tor at the same temperature. The vapor pressure of water at this temperature is 26.02 torr. According to Raoult's Law, the vapor pressure of a solution of two volatile components can be calculated by the formula. 1. At 25 degrees C, the vapor pressure of pure pentane is 511 torr and that of hexane is 150 torr. Determine the boiling point of GaCl3 under a pressure of 250 torr. The vapor pressure of liquid nitrogen is 28.1 torr at 216 Celsius and 47.0 torr at 213 Celsius. {/eq} = 94 torr, vapor pressure of ethanol at 20{eq}\rm ^\circ C What is the vapor pressure at 20.0C of a solution prepared by mixing 31.0 g methanol and 59.0 g ethanol? 126.8 A certain liquid has a vapor pressure of 92.0 Torr at 23.0 C and 376.0 Torr at 45.0 C. Calculate the value of ?H vap for this liquid. a. How does Charle's law relate to breathing? Determine the boiling point of Cl2O7 under a pressure of 125 torr. Calculate the vapor pressure of benzene at 26 degrees Celsius. The vapor pressure for methanol and ethanol at 50 C is 406 and 222 Torr, respectively. Question: W See Periodic Ta At 20.0C, the vapor pressure of ethanol is 45.0 torr, and the vapor pressure of methanol is 92.0 torr. Question: The vapor pressure of methanol, C H 3 O H , is 94 tor at 20 C. {/eq}, moles of ethanol = {eq}\rm \frac{mass}{molar~mass} Octane has a vapor pressure of 40 torr at 45.1 degrees Celsius and 400 torr at 104 degrees Celsius. The vapor pressure of water at 0 is 4.58 torr? What is the partial pressure of He? Using Raoult's law, calculate the mole fra. 1) visit? A 1.0 m solution of HCl in benzene has a freezing point of 0.4 C. So, for example, methanol has a vapor pressure of 94 torr at 25 C, and ethanol has a vapor pressure of 44 torr at 25 C. Therefore, 81.8 g of water. {/eq}. Calculate the total vapor pressure above a solution of {eq}\displaystyle A certain liquid has a vapor pressure of 92.0 Torr at 23.0 C and 369.0 Torr at 45.0 C Calculate the value of AH vap for this liquid. At 20.0 degrees C, the vapor pressure of ethanol is 43.7 mmHg. a. Calculate S for 1 mol of Hg vapor at 298.15 K if its pressure at that temperature is 0.001960 torr. Explanation: Thus at room temperature, the substance with the lowest boiling point will have the highest vapor pressure (easiest to get into the gas phase). \text{(46.07 g/mol)}, C_2H_5OH, \text{ is 44 torr } A solution is composed of 1.20 mol cyclohexane(P_{cy} = 97.6 torr) and 2.40 mol acetone (P_{ac} = 229.5 torr). What is its vapor pressure at 95 ^oC? Calculate the vapor pressure in mmHg and torr. What is causing the plague in Thebes and how can it be fixed? The mole fraction of methanol and ethanol in the vapor is 0.75 and 0.25 respectively. 10.6 torr The vapor pressure of methanol (32.043 g/mol), CH_3OH, is 94 torr at 20^o C. The vapor pressure At 25 degrees Celsius, the vapor pressure of ethanol is 45 torr when pure. Stop procrastinating with our smart planner features. Calculate Z_real. The vapor pressure of water at 16 degrees Celsius is 13.6 torr and it is 15.5 torr at 18 degrees Celsius. Mercury The total pressure in a flask containing air and ethanol at 257 degrees C is 900 mmHg. Compare with the result from the ideal gas law. Ans . Analytical cookies are used to understand how visitors interact with the website. At 20 degrees celcius , the vapor pressur of ethanol is 45 torr Given a mixture at 50 degrees Celsius that contains 0.2 mol of methanol and 0.1 mol of ethanol, compute the partial pressures of each liquid and the to, The vapor pressure of water at 45.0 degrees Celsius is 71.93 torr. Okay, So the total pressure is going to be equal to the mole fraction of ethanol to zero 542 Times the vapor pressure of ethanol, which is 45 0.0 tour. What mass of propane must be mixed with 290 g of butanone to give a solution with a vapor pressure of, 1. At 20.0C, the vapor pressure of ethanol is 45.0 torr, and the vapor pressure of methanol is 92.0 torr. What is the vapor pressure at 20 degree C, The vapor pressures of ethanol (C_2H_5OH) and 1-propanol (C_3H_7OH) at 35 ?C are 100 mmHg and 37.6 mmHg, respectively. Explain the reasons for the difference in the two procedures. The partial pressure of a gas is a pressure exerted by an individual gas in a mixture of gases. 1. Calculate the density of NO2 gas at 0.960 atm and 34 degrees C. Chemistry Determine the quality/moisture of the vapor/water mixture. Determine the vapor pressure of a solution composed of 3.00 mol of liquid A and 1.00 mol of liquid B. 3 Which has higher vapor pressure methanol or ethanol? Calculate the partial pressure of each gas, the total pressure, and the composition of the mixture in mole percent. {/eq}. Methanol has the higher vapor pressure because its molecular weight is less than ethanol and so its intermolecular forces are less than ethanols. Methanol (methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits) is a chemical compound with chemical formula CH3OH. How many grams of chlorophyll, C55H72MgN4O5, a non-volatile, non-electrolyte, must be added to 158.9 grams of ethanol to reduce the vapor pressure to 53.08 mmHg? Which of the following gases is expected to be most soluble in water? The vapor pressures of ethanol (C_2H_5OH) and 1-propanol (C_3H_7OH) at 35 ^oC are 100 mmHg and 37.6 mmHg, respectively. {/eq}, Moles of ethanol = {eq}\rm n_{C_2H_5OH} = 0.1\ mol A mixture of 32.1 g of methanol and 49.5 g of ethanol is prepared and can be assumed to behave as an ideal solution. The substance with the highest boiling point will have the lowest vapor pressure. Its vapor pressure at 20C is 58.96 kPa. l See Periodic Table See Hint At 20.0C, the vapor pressure of ethanol is 45.0 torr, and the vapor pressure of methanol is 92.0 torr. 201.0 What is the total pressure of the mixtu, A sample of O_2 gas was collected over water at 23 degrees C and 731 torr.