Purpose: The purpose of this experiment was to determine the molar mass of unknown #43 using the derived freezing point depression. To obtain the freezing point depression, t-butyl alcohol was placed in a cold-water bath and frozen solid for a total of two runs. Then, unknown #43 was dissolved in t-butyl alcohol and placed in a cold-water bath until frozen solid. This process was repeated for a total of three runs, with the first two runs containing half of the unknown, and the last run containing the full amount of unknown. Using the equation m = ΔTf/Kf , the molality of the unknown solution was found. Then, moles of unknown were calculated, which was used to calculate the average molar mass of unknown. Theory: After the experiment was completed, the data …show more content…
Using the data from the first two columns, an x-y scatterplot graph was created. Analyzing the graph, a set of points that formed a linear curve were identified, and the plot of the graph was reduced to these points. This is the initial cooling curve. A second series was then added to the graph, with points that correspond to the interval when t-butyl alcohol was freezing. A trendline was then created for each of the series to obtain the equation of the line and r values. The equations for both trendlines were then set equal to each other to obtain the x value, which was then inputted back into one of the trendline equations to obtain the freezing point (y value). This process was repeated for each of the unknown …show more content…
Modifications of this procedure include the use of hot plates instead of Bunsen burners, and heating t-butyl alcohol to 60-65 ℃ instead of 50 ℃. Other modifications include the use of weighing boats to measure an amount of unknown instead of weighing paper, and completing one run of unknown 2 instead of two runs of unknown 2. Summary of
In the first part of the experiment, Part A, the standard solutions were prepared. As a whole, the experiment was conducted by four people, however, for Part A, the group was split in two to prepare the two different solutions. Calibrations curves were created for the standard solutions of both Red 40 and Blue 1. Each solution was treated with a serial 2-fold dilution to gain different concentrations of each solution.
The temperature probe was kept in the calorimeter until the temperature had been stabilized and was calibrated. A beaker was placed on a hot plate with dial turned between three and four. Another 100.00 ml of deionized water was added while the beaker is heating up. Using the temperature probe, the beaker was measured
Repeat steps 13-16 for two more trials to achieve precise data. Take your beaker of water (150 mL) or ice out of the freezer. Measure 50 mL of water and see if it is 10 degrees celsius (if the water’s temperature is more than 10 degrees celsius, leave it in the freezer longer. If the water is colder than 10 degrees celsius, leave it out to warm up).
Method A) Prepare a NaOH solution (approximately 0,1M NaOH) 1. Place a clean, dry glass beaker on the electronic scale. 2. Determine the mass of the glass beaker. 3.
The data in Table 1 can be represented by the exponential equation given in equation 1 below. Equation 1 is also used for Cartesian plots: Q= KH^n (1) On this type of plot a straight line is drawn representing the slope intercept form in equation 2: y= mx+b (2)
Materials: The materials that I will be utilizing during these experimentations are three to four ice cubes, one cup for measuring, six unblemished cups, one stopwatch, one hot water source, three tablets of Alka-Seltzer, one thermometer that measures from negative
37.8 °C and 36.3 °C 30-40 °C 3. 41.7 °C and 40.2 ° C 40-50 °C 4. 50 °C and 48 ° C 50-60 °C Average temperatures: (37.8+36.3)/2=37.05 °C (41.7+40.2)/2=40.95 °C (50+48)/2=49 °C Table 1 -The values of experiment Temperature (°C) Density (kg/m3) 26.5 995 37.05 992.5 40.95 991 49 990 70 984.856 80 982.524 90 980.272 100 977.93 Table 2. The values in steam table Temperature (°C) Density (kg/m3)
Trial #2 and Trial #3 were used to determine the freezing point of an aqueous solution. The “Unknown C” was used to create the aqueous solution. For Trial #2, 2.0019 grams of “Unknown C” were weighed and dissolved into the 11 dram vial. Once dissolved, the 11 dram vial was submerged into the ice bath, and the Vernier temperature probe was immersed into the 11 dram vial as well. Once the temperature of the aqueous solution reached 10°C, the temperature was recorded every 10 seconds.
Identifying a Substance Based on Its Solubility ABSTRACT The basis of this report is to elucidate an experiment where an unknown substance is identified solely based on its solubility. This experiment was conducted in a very lengthy manner due to the precise process of dissolving the unknown substance. It can be inferred that to gain accurate results in the experiment, one must have a developed understanding of how solubility is found.
I presented the data of the temperatures; 21°C, 41°C, and 28°C for each four trials and their averages. The graph presents the trend of the rate of reaction decreasing when the temperature is lower. This is shown through the average rate of reaction time being 89.5 seconds for the cold water, while in the hot water the tablet’s average reaction time was 41 seconds. Based on the graph, you can see a significant change between the two times, the average cold water time’s bar have a vast change from the average hot water time’s bar. The reason I chose a bar graph to display my data was to be able to compare distinct categories in an organized manner, while having the changes between them
It is possible that the discrepancy of the molecular weight of both acetone and the unknown volatile liquid was caused by the deviation of mass in each trial. During the trial of the experiment aluminum foil was used as a cap for the Erlenmeyer flask and by using a pin, a hole was made into the cap to insure that the gas vapors would escape during the heating process, later the Erlenmeyer flask was measured after the heating process when the gas was fully condensed; however, this procedure effected the results collected. With the usage of the aluminum foil it had resulted the presence of excess moisture build up from the water bath which then had increased the mass of the gas that had been condensed due to it being measure with both the foil and elastic band. Since, the Erlenmeyer flask was left behind with the water moisture contained in the foil; therefore, it had affected the final mass of the condensed vapor inside the flask. Although the procedure was effective and adequate results were obtained, there are some improvements that can be made towards the experiment to make it exceptional.
Background Information In this lab KCl, NaCl, and a mixture of MgCl2 and NaCl are the independent variables that all lower the freezing point of water. Ice is used as the controlled variable because it is what the salts are lowering the freezing point of. Salt (Na) weakens intermolecular forces of water, thus lowering the the freezing point. This is why in colder climates where icy roads and walkways are a liability, salt is often scattered over areas that are slick with frozen water.
Let’s assume that you had a real barometer in your lab and that you gathered the data from table 1. Make a graph with it using
Abstract: Solubility refers to how a solute is capable of dissolving in a solvent. The solubility of a solute in a solvent can be dependent on the nature and components of the solvent, of the solute being dissolved in the solvent, and also the interactions among them. This experiment was carried out in order to determine a compound’s solubility as a function or in relation to temperature. Through this experiment, the dependence or effect of solubility is being tested for an unknown substance in a given amount of water at room temperature.
The drugs were stable for at least three freeze-thaw cycles. No considerable changes were observed for the stability of the spiked urine samples after 2 weeks of storage at -20˚C. 4.8. System suitability test Resolution (Rs) is a measure of the degree of separation between two adjacent peaks. A value of 1.5 for resolution implies a complete separation of the two compounds [50]. Resolutions and other system suitability parameters (capacity factor (k/), selectivity factor (α), number of theortical plates and RSD% of retention time were calculated for atenolol and pregabalin.