Exploring Gas LawsCatherine Lozier02/12/2013Chem 1310 Section C02TA Ryan BucherLab Partners:Chelsey Arnold Sunya MorinTran GHonor Pledge: I did not copy this work from any others student(s), current students in lab or old lab reports ________________________________________________SignatureDATA AND OBSERVATIONSPart ADataPressure (mmHg) Volume (mL)1375 mmHg 5 mL925 mmHg 8 mL746 mmHg 10 mL626 mmHg 12 mL509 mmHg 15 mL454 mmHg 17 mL396 mmHg 20 mL5 8 10 12 15 17 200000000Pressure v. VolumeVolume (mL)Pressure (mmHg)0 0 0 0 0 0 00510152025f(x) = 2.43x + 2.71R² = 1Volume v. Pressure-1Pressure-1 (mmHg-1)Volume (mL)Part BHCl Volume 5 mLPressure (initial) 70.9 mmHgPressure (final) 295 mmHgTemperature 20.5ºCGas Volume 0.150 LNumber of moles (n) 0.0685 molCalculationsMg + 2HCl  MgCl2 + H25g/36.458gmol-1 = 0.137 mol HCL2HCl:1H2  0.0685 mol H2To calculate gas volume we filled the flask with water and measured the volume of that water. PV = nRT0.0933atm*0.150L = nair (0.08206 L atm mol-1 K-1) (293.65 K)Nair = 5.81 * 10-4 molNtot = 0.0691 molPH2/Ptot = nH2/ntotPH2 = 0.3882 atm*0.0685 mol/0.0691 molPH2 = 0.3848 atmPV = nRT0.3848 atm * 0.150 L = 0.0685 mol * R * 293.65 KR = 0.00287 atm L mol-1 K-1Error = 100%* (Robs – Rexp) / RexpError = 100*(0.00287 – 0.08206) / 0.08206Error = 96.5%Part CTo collect data for Part C, a flask was attached to a pressure sensor, sealed with a stopcock, and then placed in a water bath on a hot plate. A temperature probe was placed in the water, and the pressure was recorded at every ºC.Pressure (mmHg) Temp (ºC)100.0 20103.0 25104.0 26104.6 27105.1 28105.7 29106.4 30107.0 31107.6 32108.1 33108.5 34109.3 35110.0 36111.3 37111.7 38112.1 39113.7 40115.0 41115.8 42116.3 43117.0 44118.0 45118.5 46119.9 47120.1 48121.0 49122.0 50293.15299.15301.15303.15305.15307.15309.15311.15313.15315.15317.15319.15321.15323.15020406080100120140f(x) = 0.78x + 100.67R² = 0.99Pressure v. TemperatureTemperature (K)Pressure (mmHg)293.15299.15301.15303.15305.15307.15309.15311.15313.15315.15317.15319.15321.15323.1595100105110115120125f(x) = 0.78x + 100.67R² = 0.99Pressure v. TemperatureTemperature (K)Pressure (mmHg)Pressure axis adjusted for better visualization.CalculationsP = 0.7769*T + 100.670 = 0.7769*T + 100.67T = -129.6 KDISCUSSIONPart AThe objective of Part A was to apply Boyle’s gas law to a gas sample. When the temperature and inverse pressure data was plotted, it formed a linear relationship, with an R2 value of 0.9966. This indicates that the linear model used to fit the data was appropriate. This means that the gas sample behaved according to Boyle’s Law, PV = k. The slope of the graph represents the K. Because the units of volume and pressure were mL and mmHg, respectively, the slope was 2.4286 mL/mmHg. Although the measured results were closely aligned with the expectedresults, any deviations could be due to either human error in measurement, which had to be done visually, or mechanical error, as the sensors were being used at relatively low pressure. Ultimately, the sources of error had little impact on the outcome of the experiment, which showed that gas behaves according to Boyle’s law.Part BThe objective of Part B was to apply gas laws in order to determine an experimental value for the gas constant R. Using partial pressures and the ideal gas law, the value of R was calculated to be 0.00287 atm L mol-1 K-1. This is wildly inaccurate, as the actual value of R is approximately 0.08206 atm L mol-1 K-1. The error of the experiment was 96.5%. Sources of error that likely contributed to the inaccurate results include human error. Inaccurate measurement of either the magnesium or the HCl used in the reaction would have yielded a different amount of hydrogen gas. Although the differences would have been relatively small, the expected yield was small enough that even minor inaccuracies would produce large percentage differences. Another source of error could be the volume measurement. To determine the volume of the gases, the flask was filled with water, and the volume of water was measured. However, it was measured using a beaker, which is a relatively imprecise tool. Any discrepancies between the actual and measured volume would also skew the calculated R value. Overall the methodsused to calculate the experimental value of R were seriously flawed, which led to highly inaccurate results.Part CThe objective of Part C was to demonstrate the relationship between pressure and temperature. Based on the data collected, there is a linear relationship between the two variables. A linear regression was applied to the data, and the R2 value for this line was 0.9911. This indicates that the linear equation adequately describes the relationship between pressure and volume. Sources of error in this experiment would be human error in measurement. The values of pressure and temperature readings would often fluctuate over ~3 mmHg or 0.5ºC. This led to some confusion over which value to record. The data was recorded based on the estimated average value. Also, although the linear regression line fit the data well, the equation did not match with the expected values for temperature and pressure. At 0 pressure, the temperature would be expected to be 0 K. However, according to the trend line, 0 pressure corresponded to a temperature of -129.6 K, a physical impossibility. It is likely that the measurement errors contributed to this inaccuracy. DISCUSSION QUESTIONS1. The gas behaved according to Boyle’s law, as the product of pressure and volume was constant. The data followed Boyle’s law very closely, as the R2 value for the linear regression line was 0.9966. This indicates that the linear relationship expected from the data was an appropriate model. Gasses follow this model because as volume increases at a constant temperature, the collisions between molecules and the container walls are spread out over a larger surface area. This causes the total pressure of the sample to decrease.2. For part B, a sample with enough magnesium to completely react with 5 mL HCl was placed in a flask. The flask was then partially evacuated, and the evacuated pressure was recorded using a LabQuest pressuresensor that was attached to the stopcock. 5 mL HCl was then deposited into the flask via a syringeconnected to the stopcock. After the reaction between magnesium and HCl, the final pressure was recorded.To find the volume of the gases, the flask was filled with water, and the volume of the