Diffusion Lab Report

2299 WordsAug 17, 201310 Pages
1.0 Introduction 1.1 Aim and Assumptions: The aim of this experiment is to observe the rate of diffusion of diethyl ether vapour into stagnant air, and then determine the diffusivity. An error analysis of this calculation also had to be carried out. The following assumptions made were: * Diethyl Ether is an ideal gas * Partial pressure at the top of the tube was equal to zero * Mass transfer resistance between the liquid surface at the bottom of the tube is insufficient, compared with the resistance in the tube * Mole fraction of Diethyl Ether at xA,O is the same as the liquid surface 1.2 Background Information: Diffusion occurs throughout the human body, and without it, cells would not get the nutrients they need for…show more content…
Each tube looked like the one in Figure 1; however each had a different length, l. Figure 1: Measuring tubes with varying l. Each tube was then filled with 0.5mL of diethyl ether and put on a fully enclosed mass balance. The balances had an error of ±0.0001g. This allowed observation of the small increments in decreasing mass. Each different container was observed for 30minutes or until the mass loss had reached a steady state. The temperature in the room as well as the pressure was then measured using a barometer. This allowed for calculations of the diffusivity of Diethyl Ether. 3.0 Results: The average mass loss, average heat flux and average diffusivity for each container are displayed in Table 2. Each container’s dimensions are displayed in Table 1. Flask Dimensions | | Units | Small | Medium | Large | Cylinder | Length | mm | 46.06 | 104.6 | 154.86 | 129.14 | | m | 0.04606 | 0.1046 | 0.15486 | 0.12914 | Length Error | mm | 0.01 | 0.01 | 0.01 | 0.01 | Diameter | mm | 2.64 | 2.64 | 2.64 | 12.45 | Diameter Error | mm | 0.01 | 0.01 | 0.01 | 0.01 | Cross-sectional Area | m2 | 5.47E-06 | 5.47E-06 | 5.47E-06 | 1.2E-04 | Cross-sectional Area Error | m2 | 2.93E-08 | 2.93E-08 | 2.93E-08 | 1.4E-07 | Table 1: Containers used and their dimensions with errors. | Average Mass Loss (g/s) | Error | Average Heat Flux (mol/s.m²) | Error | Average DAB | error |
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