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…
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
Thermodynamics is essentially how heat energy transfers from one substance to another. In “Joe Science vs. the Water Heater,” the temperature of water in a water heater must be found without measuring the water directly from the water heater. This problem was translated to the lab by providing heated water, fish bowl thermometers, styrofoam cups, and all other instruments found in the lab. The thermometer only reaches 45 degrees celsius; therefore, thermodynamic equations need to be applied in order to find the original temperature of the hot water. We also had access to deionized water that was approximately room temperature.
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:
Matter exists in three basic states: solid, liquid, or gas. A substance experiences a phase change when the physical characteristics of that substance change from one state to another state. Perhaps the most recognizable examples of phase changes are those changes from a solid to a liquid or a liquid to a gas. When a substance goes through a phase change, there is a change in the internal energy of the substance but not the temperature of the substance (Serway, et al. 611).
When there is a heat exchange between two objects, the object’s temperature will change. The rate at which this change will occur happens according to Newton’s Law of heating and cooling. This law states the rate of temperature change is directly proportional between the two objects. The data in this lab will exhibit that an object will stay in a state of temperature equilibrium, unless the object comes in contact with another object of a different temperature. Newton’s Law of Heat and Cooling can be understood by using this formula:
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...
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
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.
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.
When heat is applied to solid water, some hydrogen bonds get so much kinetic energy that