Title and Authors Colligative Properties of an Unknown Adriana Garcia and Demonta Coleman. Chemistry 112-591 Introduction Cold-tolerant fish and animals survive the freezing waters and temperatures in which they live unlike other animals that could freeze to death due to their ability of lowering the freezing point of water in their bodies. This is due to freezing point depression, which is a colligate property, a physical property that depends on the number of solute particles in the solution. The purpose of the experiment was to determine the identity of an unknown solute by using the concept of freezing point depression. Materials and Methods The chemicals used to perform this experiment were distilled water, sodium chloride (NaCl), ice, …show more content…
The mass of an 11 dram vial was taken before and after it was filled with 15 mL of distilled water, resulting in a mass of 29.9667 grams without the distilled water and 44.7771 grams with the distilled water. The looped wire was inserted into the 11 dram vial, to be used for stirring. The 11 dram vial was then submerged into the ice bath, and the Vernier temperature probe was immersed into the 11 dram vial. Once the temperature of the distilled water reached 10°C, the temperature was recorded every 10 seconds. After the data was collected, the 11 dram vial was brought back to room temperature. 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. The 11 dram vial was brought to room temperature after the data for Trial #2 was collected. For Trial #3, an additional 2.0066 grams of “Unknown C” were weighed and dissolved into the 11 dram vial. Once “Unknown C” was dissolved, the 11 dram vial was submerged into the ice bath, and the Vernier temperature probe was immersed into the 11 …show more content…
The following formula in Figure 4 was used to determine the intersection between Trial #1 and Trial #2 and Trial #1 and Trial #3. The following formulas in Figure 5 were used to determine the depression in the freezing point was used to determine the molality of the solution, the moles of the solute present, the molar mass of the solute, and finally the unknown, in respective order. The average experimental mass was 144.5 grams per mole as shown in Figure 6, which is a 20% error from the accepted molar mass of glucose 180.16 grams per mole as is shown in Figure 7. Errors could have come from the ice bath not being cold enough, not all the powder transferred into the 11 dram vial, and not dissolving all of the powder. The usage of tap water instead of distilled water would have affected the results for tap water contains other ions which would then affected the freezing point depression. Salting icy roads and walkways lowers the freezing point of the water that forms ice which leads to melting and prevents falling snow or rain from being able to freeze.
Procedure Activity 1: Fill 6 large beaker halfway with distilled water, making sure all beakers have equal amounts of water. Cut 6 30 cm dialysis bags and label each bag with a letter, A through F. Fill each dialysis bag with 15 mL of solution A through F that corresponds with the lab on each bag. For example, bag A is filled with solution A. Measure the mass of each dialysis bag and record masses of each bag in BILL. Cover the beakers with paper towel and leave the bags in the beakers overnight. Remove the dialysis bags from the beakers and let dry.
During this lab we found the composition of an unknown substance using its melting/freezing point. To do so, we first heated up the substance until it melted, by using a hot water bath. Next, we let it cool at a constant rate while measuring its temperature data using an online program. From this data, we were then able to obtain a melting/freezing point for that data, which was found to be 61.0°C. Once we had that information, we compared it to accepted values of various alcohols and acids.
Discussion: 1. In this graph the temperature that the beaker started of at was at -2 degrees because it had just came out of the freezer for 48 hours. There were times where the graph plateaued out and times when the graph had an incline. There was an incline when the results reached 42 degrees until it reached 90 degrees. The graph plateaued out when the temperature reached 26 degrees and stayed on for one minute (4mins to 5mins).
My main question is: At which temperature will children 's multivitamins dissolve the quickest when placed in water at different temperatures (0°C,50°C and 100°C)? My hypothesis for this question is that the children 's multivitamin will dissolve differently when placed under different water temperatures. I predict that the multivitamins will dissolve very fast when placed in the hot water ( in this experiment 100°C), and will dissolve very slowly when placed in the ice cold water (in this experiment, 0°C).My prediction is based on alot of things that are dissolvable. Dissolve more quicker in hot water than cold water as it has more concentration.
Introduction: The melting point of a pure substance is a characteristic that is physically consistent with each specific substance. When a substance is impure, it causes the melting point to decrease and the range of the melting point to increase. In order to identify a pure substance, it must be purified in order to get an accurate melting point estimation. Purification can be done through crystallization.
Molar Mass Molar mass is the mass of 6.022 x 1023 atoms. M of compounds is the sum of the elements that the compound is made up of. Freezing-Point Depression Freezing-point depression is when you add a solute to a solvent, which decreases the freezing-point of said solvent. This process is used for melting ice, and keeping liquids from freezing in the winter.
Lastly, it told us to repeat the same steps until we had three calcium chloride scoops in the beaker and repeat for two more trials for accurate results. To sum up the experiment, it said to record the average change in temperatures to the class averages to graph a bar graph comparing both of the averages. That’s the procedure on how to conduct the experiment correctly. The averages that my group received for zero scoops were 0.5 degrees Celsius, one scoop was 6.5 degrees
Weighed 1 gram of NaC2H3O2 and mixed it with ionized water. Boiled 12 mL of 1.0M Acetic Acid added into a beaker containing the sodium carbonate on a hot plate until all the liquid is evaporated
Calculate the density of the water then compare the measured density of the water with the value from the handbook for the temperature of this lab experiment. Now grab an unknown liquid and record the ID number and determine and verify the density of the unknown liquid. The same method is to be used as described for water. III. Prepare solutions of solutions of sodium chloride in distilled water consisting of the following percentages by weight: 5%, 10%, 15%, 20%, and 25%.
The purpose of this experiment was to find out if table salt, Epsom salt, kosher salt, or sea salt can be more affective in melting ice faster. After performing the experiment, my hypothesis that table salt would melt the ice cube faster than using kosher salt, sea salt, or Epsom salt was proven to be correct. The table salt took the least amount of time to melt the ice cube with an average of 24 minutes. Then came kosher salt with an average time of 31 minutes. Thirdly was the sea salt with an average of 33 minutes.
Abstract— “An explanation for why hot water will sometime freeze more rapidly than cold water is offered. Two specimens of water from the same source will often have different spontaneous freezing temperatures; that is, the temperature at which freezing begins. When both specimens supercool and the spontaneous freezing temperature of the hot water is higher than that of the cold water, then the hot water will usually freeze first, if all other conditions are equal and remain so during cooling. The probability that the hot water will freeze first if it has the higher spontaneous freezing temperature will be larger for a larger difference in spontaneous freezing temperature. The keys to observing hot water freezing before cold water are supercooling the water and having a significant difference in the spontaneous freezing temperature of the two water specimens”.
The boiling point of the water increases when NaCl is added to it but the ice point of water decreases when NaCl is added to it. Our result supports the hypothesis where the boiling point increases from 96 °C to 99.5 °C. However the result for the ice point increases when NaCl is added.
I could not allow myself to waste my time on something I viewed as below me. Glancing over the available lab equipment, I noticed that instead of a normal mercury thermometer, I was provided with an interesting piece of technology - a Vernier LabQuest. Turning it over in my hands, I made my first discovery: five sensor ports were placed evenly along the top. I had to track the temperature of only four flasks. The faintest beginnings of an idea flickered in my head.
For example, for unknown A, by taking an average of the class data, excluding the outlier of 377.13 g//mol, it can be concluded that the average molar mass is about 63 g/mol, which is closest to potassium chloride with a molar mas of 74.551 g/mol. Moreover, by excluding the outlier of 934.57 g/mol from another group and the personal molar mass determined by this personal experiment of 758.38 g/mol, the average molar mass is about 260 g/mol, which is closest to table sugar with a molar mass of 342.297 g/mol. Similarly for unknown C, excluding the outlier of 377.13 g/mol, the average molar mass is about 60 g/mol, which is closest to sodium chloride with a molar mass of 58.443 g/mol. Nevertheless, the molar masses determined from the personal experiment was lower than what was expected, with molar masses of 39.069 g/mol for unknown A, 758.38 g/mol for unknown B, and 42.26 g/mol for unknown C.
Aim: To find out the relationship between the greater concentration of sodium thiosulfate when mixed with hydrochloric acid and the time it takes for the reaction (the time it takes for the solution to turn cloudy) to take place and to show the effect on the rate of reaction when the concentration of one of the reactants change. Introduction: The theory of this experiment is that sodium thiosulfate and hydrochloric acid reach together to produce sulfur as one of its products. Sulfur is a yellow precipitate so, the solution will turn to yellow color while the reaction is occurring and it will continue until it will slowly turn completely opaque. The reaction of the experiment happens with this formula: “Na2 S2 O3 + HCL =