Freezing point depression: First, the freezing point depression of magnesium chloride was found. To begin, an ice bath was created in a 600 mL beaker filled with ice provided in the laboratory and rock salt. Next, Four different solutions with concentrations of 0.0 g (control), 0.2 g, 0.4 g, and 0.6g of magnesium chloride and 15 mL of deionized water were created. Each solution was made in a 100 mL beaker. The solutions containing magnesium chloride were stirred with a glass rod until the salt was completely dissolved. All equipment was cleaned with deionized water to minimize cross contamination. To calculate the freezing point, a Vernier temperature probe provided in the laboratory was used. The temperature probe was plugged into the GoLink! …show more content…
The temperature probe was placed into the test tube and recorded the temperature of the freezing solution using Logger Pro software. The test tube was held against the inner glass of the ice bath beaker so the test tube was visible to see when the solution froze over. Once the freezing point was measured, the temperature stopped being monitored and the data was recorded. The steps mentioned above for finding the freezing point, also known as ΔTf, was replicated for the 0.0, 0.4, and 0.6 concentrations. To find the freezing point depression, the equation ΔTf = imKf was used. The molality (m) of each solution was then calculated dividing moles of solute by kilograms of solvent, and the Kf value for magnesium chloride is known to be -1.86. Since magnesium chloride breaks down into three ions in deionized water, it was concluded that the Van’t Hoff factor couldn’t exceed three. For better accuracy, the experiment explained above for finding the freezing point depression and Van’t Hoff factor was re-conducted exactly the same to determine more accurate results. Again, the molality of each solution was calculated, and a graph expressing the change in freezing temperature verses molality …show more content…
First, a calorimeter was constructed with three standard styrofoam cups. One cup was stacked within the second for insulation, while the third cup was cut in half to be used as a lid. The lid was made to increase accuracy when recording the temperature. The temperature probe hooked up to Logger Pro software poked a hole in the top of the calorimeter by applied force with the end of the probe through the Styrofoam. Meanwhile, 40mL of deionized water were measured out in two clean 50 mL graduated cylinders, and poured into 100 mL beakers. The beakers and graduated cylinders were cleaned with deionized water to avoid contamination that may cause error. One of the beakers was placed onto a hot plate, which was used to heat the water in the beaker. The other beaker rested at room temperature. Once heated and at room temperature, the initial temperature was measured with the probe. Next, the two 40 mL of deionized water were poured into the calorimeter, quickly sealed with the lid, and the temperature probe emerged through the top of the calorimeter into the water to measure the temperature so the calorimeter constant would be determined. The equations used to determine the calorimeter constant were Δq = mCΔT and Δq =
Using the calorimeter, we firstly needed to calibrate the machine; to do this we took a tube of distilled water and tested it; we knew that this should measure 0 because distilled water is completely transparent. We could have done this with any known reference sample. Once we had calibrated the machine we could then test the real samples for their transparency, we tested all five of these samples a total of three times each. Between each different concentration of solution sample we had to re calibrate the machine using the distilled water again, so in total we did 20 colourimetry tests. We gained three results for each concentration of sample and then calculated an average from these three results; these are shown in the table below.
Firstly, when testing temperatures at 30°C and 40°C, the water was. sometimes heated more than needed, so I had to wait until it cooled. down to the required temperature. To avoid this happening, a. thermostatic water bath could have been used, because I could set it. to the required temperature.
To gain reliable results we needed a temperature rise of 50 degrees centigrade in the quickest time. possible. Then we can do it. Using the Propanol burner with different volumes of water we. tested the flame at varying distances under the calorimeter measured.
By adding fresh cold water it should cool the copper calorimeter. By making sure I do these checks before I do the experiment means that I should be able to get accurate results as the test will have been run fairly and hopefully successfully as there should not have been anything gone wrong. To make sure all the measurements are correct, I will also run checks. These checks when recording the data are. Make sure to check the thermometer to see what temperature the water is at the start, so I am able to see what it has to be when its been heated by 10 degrees.
A hot plate is acquired and plugged in and if left to warm up. Fill two beakers with 0.075kg of water and record the temperature using a thermometer and record it. Place one of the beakers onto the hot plate and drop one of the metal objects in. Wait for the water to boil and wait two minutes. Take the object out of the water and drop it into the other beaker. Take the temperature of the beaker and record the rise in temperature.
Tf-Ti). Next, subtract the initial temperature, 25 degrees from the final temperature, 29 degrees putting the change in temperature at 4 °C. To calculate the heat absorbed by the water in calorimeter, use the formula (q = mCΔT). Plug in 50 mL for (m), 4.184 J for (C) and 4 °C for the initial temperature (ΔT), then multiply.
Experimental Summary: First, my partner and I put the marshmallow and cheese puff on T-pins and used the Electronic Balance to measure the mass of each of them. Next, we put 100 mL of water in the 100 mL Graduated Cylinder and poured it into the 12 oz. soda can. We measured the temperature of the water with the thermometer. After
In a Styrofoam cup, record the temperature of the 200 ml of cold water. This is 200 g of water, as the density of water is 1 g/ml.
Freezing is a big part of this experiment. When liquids freeze it becomes ice, the molecules begin to form a crystal lattice, which pushes them apart. However, when a liquid is frozen it has taken up to 9% more room than it did when it was a liquid. Another word for freezing is solidifying. But, the purity of a compound can influence at when the liquid to solid change takes place. Most substances freeze at the exact same temperature that they melt. But did you know that hot water freezes faster than cold water? As the water warms up it becomes less dense, the hydrogen bonds stretch and the molecules move farther apart when these hydrogen bonds stretch they allow the covalent bonds to shrink and release their energy. This is equivalent to cooling. So, hot
The objective during this experiment was to discover the effects sodium chloride has on ice/water mixtures. More specifically how it affects the mixture’s temperature and freezing point. This was tested through seven different trials with increasing amounts of sodium chloride in each separate test. In order to conduct this analysis one must understand the meaning of the terms ‘independent’ and ‘dependant’ variable. An independent variable is a factor in the experiment that is unaffected by the other variables, whereas a dependant variable is one that will change due to other components of the experiment. In this instance the independent variable would be the sodium chloride. It is the controlled substance that does not change due to the other
In a 100ml beaker 30mls of water was placed the temperature of the water was recorded. 1 teaspoon of Ammonium Nitrate was added to the water and stirred until dissolved. The temperature was then recorded again. This was to see the difference between the initial temperature and the final temperature.
Cryogenics is a largely growing field, relatively innovative in the field of science and research. It deals with freezing temperatures below –150 degrees Celsius (-238 degrees Fahrenheit) using oxygen, helium I, helium II (which are both are chemically identical), and nitrogen. These are cooled to the point of liquidation and used to freeze diverse materials and substances. “At these extreme conditions, such properties of materials as strength, thermal conductivity, ductility and electrical resistance are altered…materials at cryogenic temperatures are as close to a static and highly ordered state as possible.” Cryogenics is more than the term for freezing, but more precisely for temperatures below –150 degrees Celsius. “Cryogenic temperatures are achieved either by rapid evaporation of volatile liquids or by the expansion of gases confined initially at pressures of 150-200 atmospheres.” This ability to freeze materials at such low temperature aids in the exploration of human research and development as well as freeze-dried foods, and aeronautics.
For this experiment, you will need 3 - ceramic bar magnets numbered 1 – 3 for identification purposes, 48 - 5/16” steel flat washers, tongs, goggles, gloves, stove, pot with boiling water, freezer, cooking thermometer, and freezer thermometer. Place the three magnets in the freezer overnight so that they reach a freezing temperature of between 0° - 32°. A freezer thermometer was used to verify temperature. After the magnets have reached the desired temperature, then place two even stacks of steel washers next to each other on a flat surface. Using one fro...
“Cream of Ice” as it was referred to back in the 17th century, was a similar dessert that was introduced to France in 1553 by Catherine de Medici. Ice cream was not available to the universal public till 1660. “A kind of ice-cream was invented in China about 200 BC, when a milk and rice mixture was frozen by packing it into snow.” (CBBC Newsround) Different types of ice cream can take different amounts of times to freeze, so the purpose of this experiment is to find out if different amounts of salt affect ice creams freezing time. This would help many ice cream businesses if they would need to add more salt or decrease the salt in their ice cream recipes.
Water is denser as a liquid than a solid. At 4°C, water is at its highest density and becomes less dense as the temperature decreases. This property is practical as it helps insulate aquatic organisms. This is because cold water forms ice at the surface. Furthermore, because water must expend a large amount of heat energy to freeze, it makes the process of ice crystallization less likely, which is extremely beneficial to membranes as this process could be quite