WEBVTT 01-01 00:00:00.180 --> 00:00:03.785 Welcome to this practical demonstration of Lab One. 01-02 00:00:03.965 --> 00:00:09.213 In our first classroom session, you began working with the lab independently. 01-03 00:00:09.393 --> 00:00:16.903 This video now shows the complete workflow, from choosing the system to saving your results and reopening them. 01-04 00:00:17.083 --> 00:00:21.648 Open the demonstration guide and keep page one beside the lab. 01-05 00:00:21.828 --> 00:00:25.007 Use the Lab One link on this video page. 01-06 00:00:25.187 --> 00:00:30.349 You can pause whenever you need to enter a value or write a calculation. 01-07 00:00:30.529 --> 00:00:36.268 The two activity stops give you time to make predictions and try a new pressure yourself. 01-08 00:00:36.448 --> 00:00:41.525 We will study one synthetic ideal binary mixture at a fixed temperature. 01-09 00:00:41.705 --> 00:00:46.868 Our main question is how pressure changes the liquid and vapor amounts. 01-10 00:00:47.048 --> 00:00:55.581 We will distinguish composition from amount, check both component balances, and preserve three cases in a comparison file. 01-11 00:00:55.761 --> 00:00:58.940 The lab contains controls for later topics. 01-12 00:00:59.120 --> 00:01:05.115 For this demonstration, stay with the ideal solution and the pressure comparison shown here. 01-13 00:01:05.295 --> 00:01:11.460 You do not need the additional model exercises to follow this first-week workflow. 02-01 00:01:13.990 --> 00:01:18.107 Under Chemical system, choose Teaching binary, synthetic. 02-02 00:01:18.287 --> 00:01:21.594 Under Liquid model, keep Ideal solution. 02-03 00:01:21.774 --> 00:01:27.129 The extra symbols in this option belong to notation used later in the course. 02-04 00:01:27.309 --> 00:01:30.189 We only need the ideal assumption today. 02-05 00:01:30.369 --> 00:01:41.199 Enter three hundred fifty kelvin for Temperature, ninety-five kilopascals for Flash pressure, and zero point five for Feed fraction, z one. 02-06 00:01:41.379 --> 00:01:44.089 Then select Calculate equilibrium. 02-07 00:01:44.269 --> 00:01:50.199 The numerical inputs are preferable to the sliders when reproducing an exact case. 02-08 00:01:50.379 --> 00:02:02.646 At this temperature, the selected property record defines saturation pressures of one hundred fifty kilopascals for component A and sixty kilopascals for component B. 02-09 00:02:02.826 --> 00:02:08.245 These are synthetic teaching values, not measurements of a real chemical mixture. 02-10 00:02:08.425 --> 00:02:15.465 They come from the chosen system, so there are no separate saturation-pressure boxes to fill in for this case. 02-11 00:02:15.645 --> 00:02:21.426 Keep temperature and feed composition unchanged throughout the pressure comparison. 02-12 00:02:21.606 --> 00:02:27.217 On our one-mole feed basis, the feed contains half a mole of each component. 02-13 00:02:27.397 --> 00:02:34.716 Record the system, ideal assumption, temperature, pressure, and feed composition on guide page one. 03-01 00:02:37.246 --> 00:02:42.814 The lab may already display the ninety-five-kilopascal baseline when it opens. 03-02 00:02:42.994 --> 00:02:44.551 That is expected. 03-03 00:02:44.731 --> 00:02:48.955 Our predictions concern the two pressures we have not tried yet. 03-04 00:02:49.135 --> 00:02:58.543 Before changing the pressure, use guide page one to predict what happens at one hundred ten kilopascals and at eighty kilopascals. 03-05 00:02:58.723 --> 00:03:04.777 For each case, write whether you expect liquid only, vapor only, or both phases. 03-06 00:03:04.957 --> 00:03:10.930 Then predict whether the vapor fraction increases or decreases relative to the baseline. 03-07 00:03:11.110 --> 00:03:18.406 In the prediction control, consider the question about lowering pressure at fixed temperature and feed composition. 03-08 00:03:18.586 --> 00:03:21.701 Make your own choice before checking the results. 03-09 00:03:21.881 --> 00:03:24.995 Give a short physical explanation in the guide. 03-10 00:03:25.175 --> 00:03:29.378 Do not change temperature to produce your predicted outcome. 03-11 00:03:29.558 --> 00:03:32.374 Take about two minutes for these predictions. 03-12 00:03:32.554 --> 00:03:35.477 A brief sentence for each pressure is enough. 03-13 00:03:35.657 --> 00:03:43.657 An initial prediction can be wrong and still be useful if you later explain how the calculation changed your reasoning. 03-14 00:03:43.837 --> 00:03:47.506 Pause here and continue when both predictions are written. 04-01 00:03:50.036 --> 00:03:54.812 Select P, x, y, fixed temperature in the Diagram menu. 04-02 00:03:54.992 --> 00:03:59.088 The horizontal axis is composition of component one. 04-03 00:03:59.268 --> 00:04:01.465 The vertical axis is pressure. 04-04 00:04:01.645 --> 00:04:06.104 The solid bubble curve uses liquid composition, x one. 04-05 00:04:06.284 --> 00:04:10.401 The dashed dew curve uses vapor composition, y one. 04-06 00:04:10.581 --> 00:04:14.891 The diamond marks the overall feed at the selected pressure. 04-07 00:04:15.071 --> 00:04:18.697 Look at the two boundary results below the diagram. 04-08 00:04:18.877 --> 00:04:25.555 Bubble pressure uses liquid composition equal to the feed composition, zero point five. 04-09 00:04:25.735 --> 00:04:31.708 Half of one hundred fifty plus half of sixty gives one hundred five kilopascals. 04-10 00:04:31.888 --> 00:04:36.901 This is where the first vapor appears when pressure is lowered from the liquid side. 04-11 00:04:37.081 --> 00:04:42.948 Dew pressure instead specifies vapor composition equal to zero point five. 04-12 00:04:43.128 --> 00:04:49.315 Its reciprocal is half divided by one hundred fifty, plus half divided by sixty. 04-13 00:04:49.495 --> 00:04:55.916 Taking the reciprocal gives approximately eighty-five point seven one four kilopascals. 04-14 00:04:56.096 --> 00:05:00.000 These boundary calculations answer different questions. 04-15 00:05:00.180 --> 00:05:08.799 Their specified compositions are not the two endpoint compositions of the current ninety-five-kilopascal tie line. 04-16 00:05:08.979 --> 00:05:15.123 Record both boundaries on guide page one and use them to classify our pressure cases. 05-01 00:05:17.653 --> 00:05:19.594 Turn to guide page two. 05-02 00:05:19.774 --> 00:05:25.679 Our flash pressure is ninety-five kilopascals, between the dew and bubble pressures. 05-03 00:05:25.859 --> 00:05:29.635 The phase label therefore reads Liquid plus vapor. 05-04 00:05:29.815 --> 00:05:32.759 Read the three large results separately. 05-05 00:05:32.939 --> 00:05:37.099 Liquid x one is about zero point three eight eight nine. 05-06 00:05:37.279 --> 00:05:41.738 Vapor y one is about zero point six one four zero. 05-07 00:05:41.918 --> 00:05:46.969 Vapor fraction, beta, is about zero point four nine three five. 05-08 00:05:47.149 --> 00:05:51.010 The first two numbers describe composition within each phase. 05-09 00:05:51.190 --> 00:05:55.307 Beta describes how much of the entire feed becomes vapor. 05-10 00:05:55.487 --> 00:06:02.037 Beta is a molar amount fraction, not the vapor composition and not a volume fraction. 05-11 00:06:02.217 --> 00:06:12.782 On a one-mole feed basis, about zero point four nine three five moles are vapor, and zero point five zero six five moles are liquid. 05-12 00:06:12.962 --> 00:06:18.978 The horizontal tie line connects the liquid and vapor compositions at the same pressure. 05-13 00:06:19.158 --> 00:06:22.252 The feed composition lies between them. 05-14 00:06:22.432 --> 00:06:26.869 Component A is more concentrated in the vapor than in the liquid. 05-15 00:06:27.049 --> 00:06:32.788 Record the baseline in the guide, keeping enough digits for the balance check that follows. 06-01 00:06:35.318 --> 00:06:39.328 Now check the answer independently on guide page two. 06-02 00:06:39.508 --> 00:06:47.060 Start with one mole of feed, containing zero point five moles of A and zero point five moles of B. 06-03 00:06:47.240 --> 00:06:55.198 For component A, multiply the liquid amount by x one, then add the vapor amount multiplied by y one. 06-04 00:06:55.378 --> 00:07:00.412 The liquid contains about zero point one nine six nine seven moles of A. 06-05 00:07:00.592 --> 00:07:05.755 The vapor contains about zero point three zero three zero three moles. 06-06 00:07:05.935 --> 00:07:08.751 Their sum is zero point five moles. 06-07 00:07:08.931 --> 00:07:14.158 For component B, use one minus x one and one minus y one. 06-08 00:07:14.338 --> 00:07:20.055 The liquid contribution is about zero point three zero nine five two moles. 06-09 00:07:20.235 --> 00:07:25.654 The vapor contribution is about zero point one nine zero four eight moles. 06-10 00:07:25.834 --> 00:07:29.012 These also sum to zero point five moles. 06-11 00:07:29.192 --> 00:07:35.166 The two phase amounts must sum to one mole, and each phase composition must sum to one. 06-12 00:07:35.346 --> 00:07:41.852 Small differences from these totals can arise if you calculate with rounded screen values. 06-13 00:07:42.032 --> 00:07:45.318 Keep additional digits during the calculation. 06-14 00:07:45.498 --> 00:07:54.781 The lab's small residual checks its equations, while your hand calculation checks that you understand the quantities being balanced. 07-01 00:07:57.311 --> 00:08:04.906 For a closer look at the amount calculation, choose Rachford, Rice, vapor fraction in the Diagram menu. 07-02 00:08:05.086 --> 00:08:10.696 You may revisit this chapter later if you first want to complete the practical workflow. 07-03 00:08:10.876 --> 00:08:18.279 For this ideal calculation, each K value is its saturation pressure divided by the flash pressure. 07-04 00:08:18.459 --> 00:08:24.944 Using kilopascals for both numerator and denominator gives dimensionless values. 07-05 00:08:25.124 --> 00:08:33.278 K one is one hundred fifty divided by ninety-five, approximately one point five seven eight nine five. 07-06 00:08:33.458 --> 00:08:40.610 K two is sixty divided by ninety-five, approximately zero point six three one five eight. 07-07 00:08:40.790 --> 00:08:44.630 The plotted function combines both component balances. 07-08 00:08:44.810 --> 00:08:51.572 At beta equal to zero it is approximately positive zero point one zero five three. 07-09 00:08:51.752 --> 00:08:58.195 At beta equal to one it is approximately negative zero point one zero eight three. 07-10 00:08:58.375 --> 00:09:01.532 The crossing between them is the physical root. 07-11 00:09:01.712 --> 00:09:11.291 That root is beta approximately zero point four nine three five, the same vapor fraction we just checked on a one-mole feed basis. 07-12 00:09:11.471 --> 00:09:18.596 The horizontal axis here is vapor fraction, unlike the composition axis of the pressure diagram. 07-13 00:09:18.776 --> 00:09:25.518 Return the Diagram menu to P, x, y, fixed temperature before saving the baseline. 08-01 00:09:28.048 --> 00:09:32.186 Before changing anything, save the calculated baseline. 08-02 00:09:32.366 --> 00:09:36.121 Open Study workspace, reopen and compare cases. 08-03 00:09:36.301 --> 00:09:43.426 In Label for the next captured case, enter a clear name such as Baseline, ninety-five kilopascals. 08-04 00:09:43.606 --> 00:09:48.790 Return to the experiment export controls and select Export experiment. 08-05 00:09:48.970 --> 00:09:59.552 This downloads a study JSON file containing inputs, calculated results, property information, and any prediction or reflection. 08-06 00:09:59.732 --> 00:10:04.873 It also adds that exported study to the workspace comparison in this tab. 08-07 00:10:05.053 --> 00:10:08.829 The case label helps you recognize the result later. 08-08 00:10:09.009 --> 00:10:17.606 Check that the captured baseline has pressure ninety-five kilopascals in its inputs and the vapor fraction we just verified. 08-09 00:10:17.786 --> 00:10:21.285 Download current inputs only is a different button. 08-10 00:10:21.465 --> 00:10:26.635 It can preserve a setup, but it does not contain the calculated result. 08-11 00:10:26.815 --> 00:10:33.450 For this exercise, use Export experiment so your evidence includes the actual calculation. 08-12 00:10:33.630 --> 00:10:37.256 The comparison currently lives in browser memory. 08-13 00:10:37.436 --> 00:10:42.407 We will download the complete comparison after adding two more pressures. 08-14 00:10:42.587 --> 00:10:50.118 Keep the individual study download as well, and do not assume that the open tab alone is permanent storage. 09-01 00:10:52.648 --> 00:10:54.845 Now test your first prediction. 09-02 00:10:55.025 --> 00:11:01.745 Change only Flash pressure to one hundred ten kilopascals and select Calculate equilibrium. 09-03 00:11:01.925 --> 00:11:10.288 Leave temperature at three hundred fifty kelvin, feed fraction at zero point five, and the liquid model ideal. 09-04 00:11:10.468 --> 00:11:15.481 The pressure is above the bubble boundary of one hundred five kilopascals. 09-05 00:11:15.661 --> 00:11:17.730 The result is Liquid only. 09-06 00:11:17.910 --> 00:11:21.750 Beta is zero, so all one mole of feed is liquid. 09-07 00:11:21.930 --> 00:11:27.712 Its composition is the feed composition, x one equal to zero point five. 09-08 00:11:27.892 --> 00:11:33.012 Vapor y one displays N A, with the explanation No vapor phase. 09-09 00:11:33.192 --> 00:11:36.754 This does not mean a vapor composition of zero. 09-10 00:11:36.934 --> 00:11:42.054 There is no bulk vapor phase whose composition we can report at this state. 09-11 00:11:42.234 --> 00:11:47.269 Compare this result with your prediction, then record it on guide page two. 09-12 00:11:47.449 --> 00:11:53.934 In the workspace, enter a new case label such as High pressure, one hundred ten kilopascals. 09-13 00:11:54.114 --> 00:11:58.061 Select Export experiment to capture this calculated case. 09-14 00:11:58.241 --> 00:12:03.916 We now have the two-phase baseline and one liquid-only case for comparison. 10-01 00:12:06.446 --> 00:12:12.547 Test the second prediction by changing only Flash pressure to eighty kilopascals. 10-02 00:12:12.727 --> 00:12:15.543 Select Calculate equilibrium again. 10-03 00:12:15.723 --> 00:12:23.446 Eighty kilopascals is below the dew boundary of about eighty-five point seven one four kilopascals. 10-04 00:12:23.626 --> 00:12:26.762 The phase label now reads Vapor only. 10-05 00:12:26.942 --> 00:12:34.046 Beta is one, and vapor y one equals the overall feed composition, zero point five. 10-06 00:12:34.226 --> 00:12:36.551 All one mole of feed is vapor. 10-07 00:12:36.731 --> 00:12:41.830 Liquid x one displays N A because there is no bulk liquid phase. 10-08 00:12:42.010 --> 00:12:46.746 As in the previous case, this absent composition is not zero. 10-09 00:12:46.926 --> 00:12:53.347 There is no liquid component amount to calculate because the liquid amount itself is zero. 10-10 00:12:53.527 --> 00:12:56.983 Record the result and compare it with your prediction. 10-11 00:12:57.163 --> 00:13:08.043 At this fixed temperature, reducing pressure from one hundred ten through ninety-five to eighty kilopascals takes us from liquid to two phases to vapor. 10-12 00:13:08.223 --> 00:13:14.623 The vapor fraction remains zero or one while a state stays inside its single-phase region. 10-13 00:13:14.803 --> 00:13:20.435 Label this case Low pressure, eighty kilopascals, and use Export experiment. 10-14 00:13:20.615 --> 00:13:23.922 The workspace should now hold three distinct cases. 11-01 00:13:26.452 --> 00:13:33.748 Open the workspace comparison and find the input pressure, phase, vapor fraction, and composition rows. 11-02 00:13:33.928 --> 00:13:40.541 Check that temperature, feed composition, and model remain the same across all three columns. 11-03 00:13:40.721 --> 00:13:43.025 Only the flash pressure changed. 11-04 00:13:43.205 --> 00:13:47.920 The comparison displays recorded fields from the exported studies. 11-05 00:13:48.100 --> 00:13:52.345 A missing phase composition may appear as Not recorded. 11-06 00:13:52.525 --> 00:13:57.965 In the underlying JSON, the absent phase composition is null. 11-07 00:13:58.145 --> 00:14:02.540 Neither Not recorded nor null should be replaced by zero. 11-08 00:14:02.720 --> 00:14:04.960 Also inspect the pressure units. 11-09 00:14:05.140 --> 00:14:11.247 The input pressure is stored in kilopascals, but the result pressure is stored in pascals. 11-10 00:14:11.427 --> 00:14:19.150 Ninety-five kilopascals and ninety-five thousand pascals represent the same pressure, not a disagreement. 11-11 00:14:19.330 --> 00:14:24.258 Use Curve CSV to download the selected diagram's data. 11-12 00:14:24.438 --> 00:14:31.174 For the pressure diagram, the pressure column is labeled P underscore P a, meaning pascals. 11-13 00:14:31.354 --> 00:14:36.852 This file is a sampled equilibrium curve, not the three-case comparison. 11-14 00:14:37.032 --> 00:14:45.843 Because temperature and the ideal system were unchanged, the pressure diagram itself is unchanged across our three cases. 11-15 00:14:46.023 --> 00:14:49.180 The current pressure marker and phase split move. 11-16 00:14:49.360 --> 00:14:53.904 Record a short explanation of that distinction on guide page two. 12-01 00:14:56.434 --> 00:14:58.418 Turn to guide page three. 12-02 00:14:58.598 --> 00:15:05.468 In the workspace, select Download comparison and confirm that the JSON file is saved. 12-03 00:15:05.648 --> 00:15:08.421 Keep this file before clearing anything. 12-04 00:15:08.601 --> 00:15:13.977 For this demonstration, Clear comparison removes the three in-memory cases. 12-05 00:15:14.157 --> 00:15:16.994 It does not delete your downloaded files. 12-06 00:15:17.174 --> 00:15:25.345 Now use Load studies or a comparison JSON and select the comparison file you just downloaded. 12-07 00:15:25.525 --> 00:15:28.170 The three recorded cases return. 12-08 00:15:28.350 --> 00:15:32.617 Choose Restore beside the ninety-five-kilopascal baseline. 12-09 00:15:32.797 --> 00:15:35.101 This loads its saved controls. 12-10 00:15:35.281 --> 00:15:44.315 Check the system, ideal model, temperature, pressure, and feed composition, then explicitly select Calculate equilibrium. 12-11 00:15:44.495 --> 00:15:49.338 Restoring a file and producing a fresh result are separate steps. 12-12 00:15:49.518 --> 00:15:56.984 The comparison preserves recorded evidence, while Calculate equilibrium runs the current inputs again. 12-13 00:15:57.164 --> 00:16:04.567 Verify that the fresh result is Liquid plus vapor with beta about zero point four nine three five. 12-14 00:16:04.747 --> 00:16:07.520 Check the two phase compositions as well. 12-15 00:16:07.700 --> 00:16:12.479 Record in the guide that you reopened the file and reproduced the baseline. 12-16 00:16:12.659 --> 00:16:21.800 A saved file becomes useful evidence when another person, or your future self, can recover the settings and obtain the same result. 13-01 00:16:24.330 --> 00:16:27.082 You are ready for an independent attempt. 13-02 00:16:27.262 --> 00:16:31.870 Stay on guide page three and keep the answer page closed for now. 13-03 00:16:32.050 --> 00:16:40.647 Use the same synthetic ideal mixture at three hundred fifty kelvin and feed composition zero point five. 13-04 00:16:40.827 --> 00:16:43.728 The new pressure is ninety kilopascals. 13-05 00:16:43.908 --> 00:16:48.964 Before running the lab, classify the phase using the two boundary pressures. 13-06 00:16:49.144 --> 00:16:54.798 Calculate liquid x one, vapor y one, and the vapor fraction by hand. 13-07 00:16:54.978 --> 00:17:06.417 Use the ideal bubble relation to find the liquid composition, the equilibrium relation to find the vapor composition, and the component balance to find beta. 13-08 00:17:06.597 --> 00:17:11.418 Then enter ninety kilopascals and select Calculate equilibrium. 13-09 00:17:11.598 --> 00:17:18.468 Compare your calculation with the result, and check both component balances on a one-mole feed basis. 13-10 00:17:18.648 --> 00:17:24.237 Label and export this new study if you want to retain it with your earlier cases. 13-11 00:17:24.417 --> 00:17:27.254 Allow about five minutes for your attempt. 13-12 00:17:27.434 --> 00:17:31.936 Write the substitutions and units, not just the final numbers. 13-13 00:17:32.116 --> 00:17:39.518 Continue to the final chapter and guide page four only after you have tried the calculation yourself. 14-01 00:17:42.048 --> 00:17:45.547 Now open guide page four and check your attempt. 14-02 00:17:45.727 --> 00:17:52.724 Ninety kilopascals lies between the dew and bubble pressures, so both liquid and vapor are present. 14-03 00:17:52.904 --> 00:18:01.956 From the ideal bubble relation, liquid x one equals ninety minus sixty, divided by one hundred fifty minus sixty. 14-04 00:18:02.136 --> 00:18:04.013 The result is one third. 14-05 00:18:04.193 --> 00:18:11.745 Vapor y one equals one hundred fifty times one third, divided by ninety, giving five ninths. 14-06 00:18:11.925 --> 00:18:19.349 The vapor fraction is the feed composition minus x one, divided by y one minus x one. 14-07 00:18:19.529 --> 00:18:21.385 This gives three quarters. 14-08 00:18:21.565 --> 00:18:29.288 On a one-mole feed basis, the liquid amount is one quarter of a mole and the vapor amount is three quarters. 14-09 00:18:29.468 --> 00:18:36.998 Component A contributes one twelfth of a mole in the liquid and five twelfths in the vapor, totaling half a mole. 14-10 00:18:37.178 --> 00:18:44.261 Component B contributes one sixth in the liquid and one third in the vapor, also totaling half a mole. 14-11 00:18:44.441 --> 00:18:50.372 If your answer differs, inspect the phase compositions and amount fraction separately. 14-12 00:18:50.552 --> 00:18:53.666 Retain your original attempt and correction. 14-13 00:18:53.846 --> 00:19:04.023 You have now completed the practical cycle: predict, calculate, check independently, save the evidence, and reopen it to reproduce the result.