Title: Observing what temperature the water must be at the undergo a phase change Introduction: A phase change is a result from the kinetic energy (heat) either decreasing or increasing to change the state of matter (i.e. water, liquid, or gas.) Thus saying, freezing is the phase change from a liquid to a solid which results from less kinetic energy/heat. Also, melting is the phase change from a solid to a liquid which results from adding kinetic energy/heat. So, the freezing and melting point of something is the temperature at which these phase changes occur. Therefore, a phase change will occur when a vial of 10 mL of water is placed into a cup of crushed ice mixed with four spoonfuls with 5 mL of sodium chloride for 30 minutes. If 10 mL of water is placed in an ice bath, it will then freeze at 5 degrees Celsius because the kinetic energy will leave quicker with the ice involved. The purpose of this lab is to observe what temperature the water must be to undergo a phase change. Methodology: A plastic cup was filled half way with crushed ice and mixed with four spoonfuls of 5 mL of sodium chloride. A thermometer was quickly placed inside the cup to take the temperature and the …show more content…
result was recorded on an observation sheet. Then a vial was filled with 10 mL of water. A thermometer was also placed inside to take the temperature and the result was also put on the observation sheet. After this, the vial was placed inside the plastic cup and a timer went off every three minutes. Every three minutes, the temperature for the ice bath and the vial, and some observations were recorded. This happened for 30 minutes. All data was recorded on the observation sheet. Results: Title: Freezing Water Table Time (min) Water Temperature (C) Ice Bath Temperature (C) Written Observations 0 22 degrees -13 degrees Foggy on the edge 3 10 degrees -12 degrees Misty, not frozen 6 9 degrees -9 degrees Misty 9 7 degrees -13 degrees Ice bath is melting 12 6 degrees -17 degrees Vile is foggy 15 0 degrees -17 degrees Foggy 18 -1 degrees -15 degrees Ice bath still melting 21 -3 degrees -15 degrees water starts to look frozen 24 0 degrees -15 degrees FROZEN 27 0 degrees -15 degrees FROZEN 30 0 degrees -13 degrees FROZEN Caption: This table includes data for the temperature of the water in the vial and the temperature of the ice/salt mixture every 3 minutes over a period of 30 minutes. A graph of the water temperature results is attached to the back of this lab report. Discussion of Results: Looking at the table and graph, the initial temperature of the water inside the vial was 22 degrees Celsius and the initial temperature of the ice bath was -13 degrees Celsius.
Energy transfer had occurred with the “warmer” temperature (water) tried equalizing with the “colder” temperature (ice). But, when this happened, a phase change occurred. As the table above indicates, when the water temperature reached 0 degrees Celsius, it stayed the same because the water particles were losing kinetic energy which led the particles to stop colliding. Once this happened the particles created bonds against each other which resulted in ice. This phase change occurred from the 24 minute mark all the way to the 30 minute mark. Heat of fusion had started from the 24 minutes
mark. Conclusion: The main findings of this lab is that water will freeze at 0 degrees Celsius. This can be proven directly from the graph and the table. Also, when the temperature of the water stops decreasing or increasing, a phase change is occurring. During the lab, this happened during the 24 minute mark through the 30 minute mark. The hypothesis, if 10 mL of water is placed in an ice bath, it will then freeze at 5 degrees Celsius because the kinetic energy will leave quicker with the ice involved is not supported in this lab because the water froze at 0 degrees Celsius not 5 degrees Celsius. An idea for a future lab would be to not have the salt and see what the results would be.
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
First, 100 mL of regular deionized water was measured using a 100 mL graduated cylinder. This water was then poured into the styrofoam cup that will be used to gather the hot water later. The water level was then marked using a pen on the inside of the cup. The water was then dumped out, and the cup was dried. Next, 100 mL of regular deionized water was measured using a 100 mL graduated cylinder, and the fish tank thermometer was placed in the water. Once the temperature was stabilizing in the graduated cylinder, the marked styrofoam cup was filled to the mark with hot water. Quickly, the temperature of the regular water was recorded immediately before it was poured into the styrofoam cup. The regular/hot water was mixed for a couple seconds, and the fish tank thermometer was then submerged into the water. After approximately 30 seconds, the temperature of the mixture leveled out, and was recorded. This was repeated three
The bottom of the capillary tube and the thermometer were submerged in a beaker of heating water. The water was stirred occasionally and heated very quickly. However, when the water reached 80 ˚C it was heated very slowly in order to not pass the melting point. 3. The temperature when alum melted was recorded in the data table.
According to the Brønsted-Lowry acid-base theory, an acid is a reactant that loses a hydrogen ion to another reactant. A strong acid is when virtually all the molecules of the acid ionises in water. In this experiment, the strong acid used was hydrochloric acid. This acid is formed when gaseous hydrogen chloride reacts with water according to the equation:
In addition, the water is mixed with salt, which allows the cold pack to stay cool. The mixture that occurs between the salt and the water causes an endothermic reaction, which means that heat is absorbed. Due to the heat absorption, the temperature of the solution will decrease substantially. The cold pack experiment lab allowed us, the students, to apply theories learned in class to actual real life experiments; such experiments prepare us for future tasks the will be put forth to determine. Our main trajectory through this assignment was to determine what our unknown salt was, through experimental analysis.
Shirley (2013) explains the steps of the theory; the first step is unfreezing. The unfreezing stage this is preparation stage. This is the stage when
The term snow is usually restricted to material that fall during precipitation in the form of small white ice crystals formed directly from the water vapour of the air at a temperature of less than 0°C and has not changed much since it fell. A fall of snow on a glacier surface is the first step in the formation of glacier ice, a process that is often long and complex (Cuffey and Paterson, 2010). The transformation of snow to ice occurs in the top layers of the glaciers and the time of the transformation depends mostly on the temperature. Snow develops into ice much more rapidly on Temperate glaciers, where periods of melting alternate with periods when wet snow refreezes, than in Polar glaciers, where the temperature remains well below the freezing point throughout the year. The density of new snow as it falls on glacier surface depends mostly on the weather conditions. In clam conditions, the density of new snow is ρs ≈ 50 – 70 kg m-3 (Table 1.1). If it is windy, there is breaking of the corners of snowflakes, and the density is more like ρs ≈ 100 kg m-3. After the snow has fallen on the surface, there are three processes that are all active together and work to transform the snow to ice.
Some say that the only reason glaciers are melting is because of low evaporation and not hot temperatures. That is one of the reasons , but the other is because there is some mu...
Pressure on the ice reduces the melting point. If pressure is afterward reduced, water will freeze again. This is called regelation. When a player skates across the ice, he or she applies a lot of pressure, leaving a trail of water where the blades were. Because the pressure leaves quickly, the water freezes to ice again (Haché 22). Nevertheless, pressure is not the only factor that causes this melting. Friction also takes part because it creates heat. With help...
Icing is normally encountered in when the temperatures range between 14 to 32 degrees Fahrenheit...
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.
Q is negative in this case because the water going from vapor to liquid loses energy to its surroundings during the phase change. One issue of calculating the energy given off by the condensation reaction for the picture of my iced coffee is that we do not know the mass of the water vapor being converted into water droplets. To make up for this I looked up the average humidity for Spokane in the month of April and found the mass, in grams, of the water vapor per one pound of air based on the humidity and temperature of the air (engineering tool box). From this information we can then calculate the energy given off in our specific phase change of the water vapor onto the cup containing the iced coffee. If the temperature in the room were about 80 degrees Fahrenheit, or 27 degrees Celsius, the calculated mass of the water vapor per pound of air would be about 8.1 grams or 0.0081 kg. The latent heat for condensation is the same as the latent heat for vaporization and it is 22.6 x 10^5 J/kg. Using the equation for the amount of energy given off by a pound of air reacting with the cold surface of the cup causing the phase change is as
The theories behind cold fusion are contrary to popular theory and therefore naturally run up against great resistance. Theories on why cold fusion is observed are still being developed, but a definitive theory is yet to be reached. There is a need for a new theory because cold fusion has been observed in such a verity of experiments that the possibility of error is not probable. The overwhelming number of experiments that have produced an effected dubbed ‘cold fusion’ forces a new theory to be considered.
These phases can go from one to another when affected by certain things, which is known as phase changes. To switch from a solid to a liquid, the solid must melt. On the other hand, to switch from a liquid to a solid, freezing must occur. Furthermore, to switch from a liquid to a gas, a process known as evaporation must take place. In contrast, to go from a gas to a liquid, condensation must take place. Furthermore, sublimation must take place for a solid to turn to a gas. Inversely, deposition must occur for a gas to change to a solid.
The same was true for diffusion in a liquid. The cold water diffused at a much slower rate than the room temperature water did. Though the gel and liquid are two different states of matter, the experiments both help solidify how diffusion works in different temperature settings.