pentane vapor pressure calculatorpentane vapor pressure calculator

Finding the Vapor Pressure of a Solution (Ionic-Nonvolatile Solute): Even when a solute is volatile, meaning that it has a measurable vapor pressure, we can still use Raoults law. Mixtures of benzene and toluene approximate an ideal solution because the intermolecular forces in the two pure liquids are almost identical in both kind and magnitude. Uses formula: log e P m m H g = {\displaystyle \scriptstyle \log _{e}P_{mmHg}=} log e ( 760 101.325 ) 10.41840 log e ( T + 273.15 ) 5778.024 T + 273.15 + 81.92460 + 1.178208 10 5 ( T + 273.15 ) 2 {\displaystyle \scriptstyle \log _{e}({\frac {760}{101.325}})-10.41840\log _{e}(T+273. We don't collect information from our users. The 3d structure may be viewed usingJavaorJavascript. WebVAPORPRESSUREOFHYDROCARBONSFROM0.001TO10mmHg OA TicknerandLossing ' havemeasuredthevaporpressureof elevenhydrocarbonsandCO?asafunctionoftemperaturedownto apressureof0.001mmHgusingamassspectrometer.These The vapor pressure of a solution containing 1 m of solution of glucose will be what?". Sales@DiversifiedCPC.com. Last Updated: August 30, 2022 WebThe procedure to use the vapor pressure calculator is as follows: Step 1: Enter the temperature, molar enthalpy of vaporization, and x for the unknown in the input field. Liquid Phase. PROBLEM SETUP. How to calculate vapor pressure? We can use the Omnicalculator tool Vapor pressure calculator or the Clausius Clapeyron equation as follows: Define a boiling temperature and pressure you know. Literature and Downloads | Privacy Policy | Privacy Settings Chem1 Virtual Textbook. Analogously, the amount of energy needed for a direct phase transition between a solid and gaseous state is called the enthalpy of sublimation. Recommendations : Air Liquide has gathered data on the compatibility of gases with materials to assist you in evaluating which materials to use for a gas system. At boiling point at 1.013 bar. So, the solute molar fraction is 1/56.6 ~ 1.768.10^-2. Contact the regional Air Liquide team for expertise service. Today, all this information is gathered here, just a click away! For full table with Imperial Units - rotate the screen! Vapor Pressure Calculator. Let's start with calculating the right side of our equation, as there are no unknowns: ln102325P2=1.1289\small ln\frac{102325}{P_2} = 1.1289lnP2102325=1.1289. WebCAS Registry Number:109-66-0. WebVAPORPRESSUREOFHYDROCARBONSFROM0.001TO10mmHg OA TicknerandLossing ' havemeasuredthevaporpressureof elevenhydrocarbonsandCO?asafunctionoftemperaturedownto apressureof0.001mmHgusingamassspectrometer.These 0000002508 00000 n Alternatively, if the vapor pressure at 70C is 105.37 kPa and is known, you can use the 70 to 90C temperature differential to calculate the slope and intercept and ultimately calculate pv = 35.79 psia = 246.79 kPa. For example, let's say that we have a solution made from two chemicals: benzene and toluene. WebThe emission rate of n-pentane from the tailpipes of diesel powered trucks was measured as 1,860 mg/km (6). Vapor Pressure Hexane and isooctane are both nonpolar molecules (isooctane actually has a very small dipole moment, but it is so small that it can be ignored). Ideal solutions and ideal gases are both simple models that ignore intermolecular interactions. ", https://www.chem.purdue.edu/gchelp/liquids/vpress.html, https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/States_of_Matter/Phase_Transitions/Clausius-Clapeyron_Equation, https://chemistrytalk.org/clausius-clapeyron-equation/#:~:text=The%20Clausius%2DClapeyron%20equation%20relates,log%20of%20the%20vapor%20pressure, http://chemwiki.ucdavis.edu/Physical_Chemistry/Physical_Properties_of_Matter/Solutions_and_Mixtures/Ideal_Solutions/Changes_In_Vapor_Pressure,_Raoult%27s_Law, https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Solutions_and_Mixtures/Ideal_Solutions/Changes_In_Vapor_Pressure%2C_Raoult's_Law, http://intro.chem.okstate.edu/1515SP01/Database/VPWater.html, http://www.traditionaloven.com/culinary-arts/sugars/raw-sugar/convert-liter-l-to-gram-g-raw-sugar.html, https://www.eiu.edu/eiuchem/forms/tutorial6.pdf, https://chemistrytalk.org/clausius-clapeyron-equation/, https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_General_Chemistry_(Petrucci_et_al.)/13%3A_Solutions_and_their_Physical_Properties/13.06%3A_Vapor_Pressures_of_Solutions. Vapor Pressure Requested URL: byjus.com/vapor-pressure-calculator/, User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36. pentane Equation \ref{13.6.1} is known as Raoults law, after the French chemist who developed it. <>/ProcSet[/PDF /Text /ImageB /ImageC /ImageI]/Font<>>>/MediaBox[0 0 523 721]/Contents[128 0 R]>> Eventually all of the water will evaporate from the beaker containing the liquid with the higher vapor pressure (pure water) and condense in the beaker containing the liquid with the lower vapor pressure (the glucose solution). That means that when your house pump sucks water by reducing pressure at the inlet point, it is more prone to evaporate. 1/ T3 = 0.0014888. Pentane Vapor pressure is directly related to the kinetic energy of a molecule. This is caused by a principle called vapor pressure. And what does this all have to do with the enthalpy of vaporization? The curve between the critical point and the triple point shows the pentane boiling point with changes in pressure. Both of these equations might look intimidating at first, but, once you understand them, they turn out to be very easy. Other names:n-Pentane;Skellysolve A;n-C5H12;Pentan;Pentanen;Pentani;Amyl hydride;NSC 72415. "The vapor pressure of pure water is 760mm at 25 degree Celsius. Remember to check out our other calculators, for example, the osmotic pressure calculator. Like an ideal gas, an ideal solution is a hypothetical system whose properties can be described in terms of a simple model. If you're unsure what vapor pressure is, keep scrolling. 127 0 obj PROCESS DATA. Fax: 815-423-5289 Saturation Temperature. Google use cookies for serving our ads and handling visitor statistics. For each system, compare the intermolecular interactions in the pure liquids and in the solution to decide whether the vapor pressure will be greater than that predicted by Raoults law (positive deviation), approximately equal to that predicted by Raoults law (an ideal solution), or less than the pressure predicted by Raoults law (negative deviation). We expect the AB interactions to be comparable in strength to the AA and BB interactions, leading to a vapor pressure in good agreement with that predicted by Raoults law (an ideal solution). For many years, researchers, industrials and students spent a lot of time searching the information they needed on the molecules used in their plants and laboratories, in many publications. Plug all of the known variables and constants into the equation, and isolate the unknown variable, which will be the pressure. 0000010131 00000 n <> WebThe emission rate of n-pentane from the tailpipes of diesel powered trucks was measured as 1,860 mg/km (6). Just type in the temperature, and the pressure will appear in no time - don't hesitate. Calculate the mole fraction of water (the solvent). At boiling point at 1.013 bar. Webincorporated in the new algorithm. Doubling the concentration of a given solute causes twice as many surface sites to be occupied by solute molecules, resulting in twice the decrease in vapor pressure. "I was helping my friend with a chemistry problem about vapor pressure and mole fractions. If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. Pentane Seawater is an approximately 3.0% aqueous solution of \(NaCl\) by mass with about 0.5% of other salts by mass. WebVAPORPRESSUREOFHYDROCARBONSFROM0.001TO10mmHg OA TicknerandLossing ' havemeasuredthevaporpressureof elevenhydrocarbonsandCO?asafunctionoftemperaturedownto apressureof0.001mmHgusingamassspectrometer.These 72 0 obj<>stream See also more about atmospheric pressure, and STP - Standard Temperature and Pressure & NTP - Normal Temperature and Pressure, as well as Thermophysical properties of: Acetone, Acetylene, Air, Ammonia, Argon, Benzene, Butane, Carbon dioxide, Carbon monoxide, Ethane, Ethanol, Ethylene, Helium, Hydrogen, Hydrogen sulfide, Methane, Methanol, Nitrogen, Oxygen, Propane, Toluene, Water and Heavy water, D2O. 0000000023 00000 n Webincorporated in the new algorithm. Equation source. Asked for: vapor pressure of solution. It's much easier to use a scientific calculator or, as long as you are here, our vapor pressure calculator :). As a result, fewer water molecules can enter the vapor phase per unit time, even though the surface water molecules have the same kinetic energy distribution as they would in pure water. Mixtures of different molecules are never ideal, but we can treat them as if they were to simplify our calculations. At the critical point there is no change of state when pressure is increased or if heat is added. WebPentane - Density and Specific Weight vs. Vapor The same result is obtained using either method. MORE Evaporation/Subl. Calculate the pressure, in atm, of pentane vapor in equilibrium with pentane liquid at 298 K. By using our site, you agree to our. wikiHow is where trusted research and expert knowledge come together. The Journal of Chemical Thermodynamics 1977, 9 (2) , 153-165. https://doi.org/10.1016/0021-9614(77)90081-7; D. In addition to industry-leading products, the company maintains an unmatched focus on customer satisfaction and environmental safety in all of its business operations. Method 1 Using the Clausius-Clapeyron Equation 1 Write the Clausius-Clapeyron equation. At the same time, the rate at which water molecules in the vapor phase collide with the surface and reenter the solution is unaffected. - Raoult's law. Given: identity of solute, percentage by mass, and vapor pressure of pure solvent. 0000004753 00000 n The iterative procedure calculates the vapor pressure of a liquid fraction for the conditions specified by the RVP test, namely, original sample at 35oF, pressure test started at 60oF, equilibrium vapor/liquid volume of 4 (i.e., V/L = n = 4), and final equilibrium pressure measured at 100oF. Calculate the vapor pressure of an aqueous solution containing 30.2% ethylene glycol by mass, a concentration commonly used in climates that do not get extremely cold in winter. Chemistry questions and answers. Pentane - Thermophysical Properties Figure \(\PageIndex{2}\) shows two beakers, one containing pure water and one containing an aqueous glucose solution, in a sealed chamber. hence, pv = 35.89 psia = 247.46 kPa. < ]/Info 123 0 R/Size 133/Prev 974730>> The Journal of Chemical Thermodynamics 1977, 9 (2) , 153-165. https://doi.org/10.1016/0021-9614(77)90081-7; D. WebClassic equation for vapor pressure calculation and correlation. Method 1 Using the Clausius-Clapeyron Equation 1 Write the Clausius-Clapeyron equation. xref At 100C, the vapor pressure of pure water is 760 mmHg. The iterative procedure calculates the vapor pressure of a liquid fraction for the conditions specified by the RVP test, namely, original sample at 35oF, pressure test started at 60oF, equilibrium vapor/liquid volume of 4 (i.e., V/L = n = 4), and final equilibrium pressure measured at 100oF. To find the vapor pressure at a given temperature, use the Clausius-Clapeyron equation: ln (P1/P2) = (Hvap/R) ( (1/T2) - (1/T1)). Asked for: predicted deviation from Raoults law. WebThe emission rate of n-pentane from the tailpipes of diesel powered trucks was measured as 1,860 mg/km (6). How can I solve this problem? 0000000459 00000 n WebLPG Calculator Calculate the vapor pressure and density of any blend of Propane, Isobutane, n-Butane, or Pentanes between the temperatures of -40 and 130F. 124 0 obj The vapor pressure of water calculator is a handy tool that can help in determining the vapor pressure of water and ice. I couldn't figure it out. For each system, compare the intermolecular interactions in the pure liquids with those in the solution to decide whether the vapor pressure will be greater than that predicted by Raoults law (positive deviation), approximately equal to that predicted by Raoults law (an ideal solution), or less than the pressure predicted by Raoults law (negative deviation): positive deviation (vapor pressure greater than predicted), negative deviation (vapor pressure less than predicted). Download the set of data (XLS - 82.01 KB), Latent heat of vaporization (at boiling point), Lower flammability limit (IEC 80079-20-1), Upper flammability limit (IEC 80079-20-1). For example, water boils at 100 C when pressure is 1atm. A solution of two volatile components that behaves like the solution in Figure \(\PageIndex{3}\), which is defined as a solution that obeys Raoults law. 0000007173 00000 n Give it a go! WebPropane - Density and Specific Weight vs. Methanol contains an extensive hydrogen bonding network, but in this case the polar acetone molecules create AB interactions that are stronger than the AA or BB interactions, leading to a negative enthalpy of solution and a lower vapor pressure than predicted by Raoults law (a negative deviation). N-Pentane is an organic compound with the formula C5H12. The net effect is to shift the dynamic equilibrium between water in the vapor and the liquid phases, decreasing the vapor pressure of the solution compared with the vapor pressure of the pure solvent. Stephen Lower, Professor Emeritus (Simon Fraser U.) Weblog 10 of n-Pentane vapor pressure. Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse! Hint, air pressure at 3500 m.a.s.l., at 20C is 65kPa. Step 2: Now click the button Calculate x to get the result. Antoine's Equation Permanent linkfor this species. The vapor pressure of pure water is 47.1 torr at 37 C. 0000005593 00000 n Vapor pressure 1,056.7 g, Moles (water): 1,000 grams 1 mol/18.015 g = 55.51 moles, Moles (sucrose): 1,056.7 grams 1 mol/342.2965 g = 3.08 moles (note that you can, For instance, let's say that we have an unknown liquid with a vapor pressure of 25 torr at 273 K and 150 torr at 325 K and we want to find this liquid's enthalpy of vaporization (H, 8.314 J/(K Mol) (-1.79)/(-0.00059) = H. WebCAS Registry Number:109-66-0. 0000001523 00000 n Pentane Find out the new pressure at which water will boil. Given: identity of solute, percentage by mass, and vapor pressure of pure solvent. Vapor Pressure Calculator The vapor pressure of pure water at 25C is 23.8 mmHg. Suite 216 Calculate endobj If you're unsure what vapor pressure is, keep scrolling. ln102325PaP2=40660Jmol8.3145JmolK(1263K1280K)\small ln\frac{102325Pa}{P_2} = \frac{40660\frac{J}{mol}}{8.3145 \frac{J}{mol \cdot K}\cdot (\frac{1}{263K}-\frac{1}{280K})}lnP2102325Pa=8.3145molKJ(263K1280K1)40660molJ. To understand that the total number of nonvolatile solute particles determines the decrease in vapor pressure, increase in boiling point, and decrease in freezing point of a solution versus the pure solvent. For information on how to find the vapor pressure of dissolved solutions, read on! Vapor Pressure xc```e`` Ab@#.~INY1y5ojl:mVeZ]L#u0! w)A@ to Calculate Vapor Pressure trailer We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Weblog 10 of n-Pentane vapor pressure. This kind of behavior is called a negative deviation from Raoults law. Obtain the water enthalpy of vaporization: 40660 J/mol. 0000001121 00000 n What can The Power of Purity do for you? Calculate the volume or mass of a quantity of gas or liquid, Molecule phase diagram showing the transition phases between solid, liquid and gas as a function of temperature and pressure, Examples of uses of this molecule in Industry and Healthcare, Europe (according to EN1839 for Limits and EN 14522 for autoignition temperature), US (according to ASTM E681 for Limits and ASTM E659 for autoignition temperature). In chemistry, vapor pressure is the pressure that is exerted on the walls of a sealed container when a substance in it evaporates (converts to a gas). 0000001201 00000 n If you have the temperature in Centigrade, then you need to convert it with the following formula: The methods above work because energy is directly proportional to the amount of heat supplied. HtTsF~Sg #yRak1 .0tZ^V'[i`%'JO"ZXw rK3yv)@@qD0H}iox\&Pq]HBww0v)G+O]^W.LBDrg53yU~og0)Ej43^D]m%]JYl. Conversely, vapor pressure decreases as the temperature decreases. )%2F13%253A_Solutions_and_their_Physical_Properties%2F13.06%253A_Vapor_Pressures_of_Solutions, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\), status page at https://status.libretexts.org. In your chemistry classes, a teacher might give you an exercise to find the vapor pressure or enthalpy of vaporization. Other names:n-Pentane;Skellysolve A;n-C5H12;Pentan;Pentanen;Pentani;Amyl hydride;NSC 72415. Chemical structure: This structure is also available as a 2d Mol fileor as a computed3d SD file. The phase diagram of pentane is shown below the table. 0000026810 00000 n Let's have a closer look at two vapor pressure equations: the Clausius-Clapeyron equation and Raoult's law. Vapor Pressure m (Volume) Vapor pressure: 4.649E-1 bar: Vapor pressure: 6.84E-1 bar: Applications. Chemistry questions and answers. It belongs to the organic class alkanes, and is naturally present in crude oils and condensates. WebCAS Registry Number:109-66-0. n-hexane and isooctane (2,2,4-trimethylpentane). Chemistry. The vapor pressure of benzene in a benzenetoluene solution is, \[P_{C_6H_6}=X_{C_6H_6}P^0_{C_6H_6} \label{13.6.6}\], and the vapor pressure of toluene in the solution is, \[P_{C_6H_5CH_3}=X_{C_6H_5CH_3}P^0_{C_6H_5CH3} \label{13.6.7}\]. (%u7O xsA*,"{Iz Calculate the vapor pressure and density of any blend of Propane, Isobutane, n-Butane, or Pentanes between the temperatures of -40 and 130F. WebPropane - Density and Specific Weight vs. Only emails and answers are saved in our archive. Calculate the pressure, in atm, of pentane vapor in equilibrium with pentane liquid at 298 K. The vapour pressure of n - pentane = 420 mm of Hg and n - heptane = 36 mm of Hg . Calculate For example, let's say that we're told that we have a container full of liquid at 295 K whose vapor pressure is 1 atmosphere (atm). WebPentane - Density and Specific Weight vs. Raoult's law is only accurate for ideal solutions. Science. You can target the Engineering ToolBox by using AdWords Managed Placements. Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! Let's say 100C, at 101.3kPa of atmospheric pressure. Saturation Pressure. Asked for: vapor pressure of solution. You could also use Raoult's Law to find the vapor pressure: Psolution=PsolventXsolvent . Because of its low boiling point, low cost, and relative safety, pentanes are used as a working medium in geothermal power stations in some blended refrigerants. 0000003062 00000 n Vapor Pressures of 125 0 obj Calculate the vapor pressure of an aqueous solution containing 30.2% ethylene glycol by mass, a concentration commonly used in climates that do not get extremely cold in winter. WebPentane Formula:C5H12 Molecular weight:72.1488 IUPAC Standard InChI:InChI=1S/C5H12/c1-3-5-4-2/h3-5H2,1-2H3Copy IUPAC Standard InChIKey:OFBQJSOFQDEBGM-UHFFFAOYSA-NCopy CAS Registry Number:109-66-0 Chemical structure: This structure is also available as a 2d Mol fileor as a computed3d SD file The 3d structure may be viewed using Javaor pentane Finding Vapor Pressure of a Solution (Nonionic-Volatile Solute): The vapor pressure of the solution is proportional to the mole fraction of solvent in the solution, a relationship known as Raoults law. % of people told us that this article helped them. The relationship between solution composition and vapor pressure is therefore, \[ \color{red} P_A=X_AP^0_A \label{13.6.1}\], where \(P_A\) is the vapor pressure of component A of the solution (in this case the solvent), XA is the mole fraction of A in solution, and \(P^0_A\) is the vapor pressure of pure A. It's also expressed by the following equation: Psolution=PsolventXsolvent\small P_{solution} = P_{solvent} \cdot X_{solvent}Psolution=PsolventXsolvent. Consequently, if we reduce environmental pressure as it happens in reality at higher altitudes, we get a lower boiling point. Method 1 Using the Clausius-Clapeyron Equation 1 Write the Clausius-Clapeyron equation. Vapor Pressure Saturation Pressure. Vapor Pressure Temperature and Pressure - Online calculator, figures and tables showing density and specific weight of propane, C 3 H 8, at temperatures ranging from -187 to 725 C (-305 to 1300 F) at atmospheric and higher pressure - EthaneEnter weight %'s of each component Propane Isobutane n-Butane isoPentane n-Pentane Temperature-40 to 130 oF (90oif Ethane does not = 0) Vapor Pressurepsig For information on how to find the vapor pressure of dissolved solutions, read on! Include your email address to get a message when this question is answered. Chemical structure: This structure is also available as a 2d Mol fileor as a computed3d SD file. If you're unsure what vapor pressure is, keep scrolling. Rate. As a result of the EUs General Data Protection Regulation (GDPR). The total vapor pressure of the solution (\(P_T\)) is the sum of the vapor pressures of the components: \[ \begin{align} P_T &=P_A+P_B \\[4pt] &=X_AP^0_A+X_BP^0_B \label{13.6.4} \end{align}\]. Cookies are only used in the browser to improve user experience. Accuracy: For many substances, vapor pressures are only poorly known; expect errors up to a few 10% of the vapor pressure value and up to approx. 0000010637 00000 n The vapor pressure of a solution is equal to the vapor pressure of a pure solvent times its mole fraction. You can use the Omnicalculator Vapor pressure calculator or the Clausius Claperyron equation as follows: As per the Clausius Clapeyron equation, a lower vapor pressure corresponds to a lower boiling point. We find that water at 25 C has a vapor pressure of, Let's say that our recipe for simple syrup uses, Mass (1 L of raw sugar): Approx. Density of pentane with varying temperature and pressure. But if you're solving the Clausius-Clapeyron equation on your own, remember that temperature should always be expressed in Kelvins. Solve the equation for the pressure by following the order of operations. Try this helium balloons calculator! Chemistry. How is vapor pressure affected by temperature? Pentane is a liquid at standard conditions. If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. 70 24 Adding a nonvolatile solute, one whose vapor pressure is too low to measure readily, to a volatile solvent decreases the vapor pressure of the solvent. We can use the Omnicalculator tool Vapor pressure calculator or the Clausius Clapeyron equation as follows: Define a boiling temperature and pressure you know. Science. Water has an enthalpy of vaporization of 40660. %PDF-1.4 % Now you know how to calculate vapor pressure on your own. MORE Evaporation/Subl. To use Raoults law to calculate the vapor pressure of the solution, we must know the mole fraction of water. The G of vaporization for pentane at 298 K and 1.00 atm is 0.03176 kJ/mol. You can rearrange the above equation to solve for P2\footnotesize P_2P2: P2=102325e1.1289=33090Pa\small P_2 = \frac{102325}{e^{1.1289}} = 33090\space PaP2=e1.1289102325=33090Pa. As you see, it's a bit complicated to do this calculation by hand. n-Pentane concentrations in gasoline and gasoline powered tailpipe emissions were 27,600 ug/g gasoline, 4,290 ug/km in a catalyst-equipped engine, 536,000 ug/km in a noncatalyst-equipped engine (7).