Thermochemistry is the study of energy changes that occur during chemical reactions and changes in state. There are two different processes that have to do with the absorption and release of heat. In the endothermic process, the system picks up heat, as the surroundings lose heat. In the exothermic process, heat is released to its surroundings. Heat either goes in or goes out. We are going to make ice cream and we are going to identify which of these two different processes is used.
Materials
• 3 cups of ice
• ¼ of a cup of rock salt
• 1 pint of whole milk
• ½ tbs. of vanilla extract
• 2 Oreo cookies
• 4 tbs. of chocolate powder
• Medium sized Ziploc bag
• Large sized Ziploc bag
• Towel
• 3 tbs. sugar
• A plastic spoon
Procedures
Ice was added
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It is the changes in energy by the state it’s going through. The mixture converts into a solid because of the change of its surroundings, which was the bag with ice and rock salt. This lab project helps us see the changes on temperature and how the milk was affected to this change.
Post Lab Questions
1. Is the freezing an exothermic or endothermic?
a. Endothermic
2. Why did the outside of the bag get wet? (assume your bag did not leak)
a. The ice was melting due to the heat of our bodies released.
3. Describe the transfers of the energy that occurred in the lab between the air and the bag and between the ice cream and salted ice.
a. The air filled the bag and the ice cream was formed because the melted ice gave it coldness.
4. What happened shortly after you added the salt to the ice cubes? Was the temperature above or below the freezing point of the water?
a. The salt reduced the temperature. The temperature went below the freezing point.
5. What does this tell you about the freezing point of fresh water lake or salt water ocean?
a. The freezing point of fresh water of lake is not as cold as the salt water of the ocean because of the
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
Finding Out Which Fuel Releases the Most Energy Per Gram. Aim: To be able to Find out which fuel releases the most energy per gram. Scientific Theory: What is the Science of Heat is the transfer of energy between two objects due to a temperature. The sand is a sand.
In this lab, I determined the amount of heat exchanged in four different chemical reactions only using two different compounds and water. The two compounds used were Magnesium Hydroxide and Citric Acid. Both compounds were in there solid states in powder form. Magnesium Hydroxide was mixed with water and the change in heat was measured using a thermometer. The next reaction combined citric acid and magnesium hydroxide in water. The change in heat was measured as well. For the third reaction citric acid was placed in water to measure the change in heat. In the last reaction, citric acid was combined with water. The heat exchanged was again measured. It is obvious we were studying the calorimetry of each reaction. We used a calorimeter
An exothermic reaction is one, which gives out energy to the surroundings usually in the form of heat and is shown by a rise in temperature. This is because, during a chemical reaction old bonds are broken and new bonds are formed; the
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.
Thermodynamic equilibrium leads to the large-scale definition of temperature, as opposed to the small-scale definition related to the kinetic energy of the molecules. The first law of thermodynamics relates the various forms of kinetic and potential energy in a system to the work which a system can do and to the transfer of heat. This law is sometimes taken as a definition internal energy, and introduces an extra state variable, enthalpy. The first law of thermodynamics allows for many possible states of a system to exist. But experience indicates that only certain states occur. This leads to the second law of thermodynamics and contrast between another state variable called entropy. The second law stipulates that the total entropy of a system plus its environment can not decrease; it can remain constant for a reversible process but must always increase for an irreversible process. Thermal energy is the energy a substance or system has due to its temperature, i.e., the energy of moving or vibrating molecule. Thermodynamics involves measuring this energy, which can "exceedingly complicated," according to David McKee, a professor of physics at Missouri Southern State University. "The systems that we study in thermodynamics … consist of very large numbers of atoms or molecules interacting in complicated ways. But, if these systems meet the right criteria, which we call equilibrium, discovered with a very small number of measurements or
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...
Conduction can be seen when the ice touched the cans full of insulation. The cooled cans touched the installation inside the can making it cooler. Convection can be found al over the place in our experiments. When we heated our model dwelling with the heat lamp the outside of the house heated. This in turn heated the air inside making the air temperature rise.
If the temperature increased, then there would be an increase in the amount of fat mass production. This theory was refuted and showed no effect of the amount of production in the end of the procedure. The effect of temperature on fat mass production resulted in the same percentages of fat in all various temperatures. The reason; the amount of cream used was not manipulated. If the amount of cream changed; that would become a contraceptive experiment. The time butter separation occurred took to form butter varied, because of the different temperatures the creams were kept at had an effect on the time the formation process took. One question is why can butter form in the first place from this liquid. The reason butter appeared is because the cream was produced before homogenization. The cream contains fat, which includes different parts. As shaking the container filled with cream. The individual fat particles experience fission. Eventually, the whole mass has separated and created a solid butter cream. These results have occurred at every temperature to help support the conclusion that the temperature had no effect on the percentage produced at the end of the data
Thermal Energy: Matter is made up of particles called molecules. A rise in the temperature of matter makes these particles move and vibrate faster. The energy that comes from the temperature of the matter is called thermal energy. Eg: When we boil water, the molecules start moving faster, causing it to heat. This boiling water has thermal energy.
Heat is a type of energy that transfers between two pieces of matter that have different temperatures. There are three ways heat can be transferred. The first way is through radiation and the second is convection. The third way is through conduction which is when an object or material conducts the heat from one substance through itself and to another. This is the method I will be focusing on.
IS THERE ANY WATER or LIQUID ON ICE? KEYWORDS Liquid like layer, ice slipperiness, melting pressure, frictional heating, chemical bonds ABSTRACT Being an engineer and being interested in the questions which many of us do not notice pushed me to research that topic. Moreover, I would like all readers to realize how scientific experiments answer the questions which is hard to be replied. At the end, I learnt how physical and chemical explaination involve in the answer of question, which is why ice is slippery. İNTRODUCTİON
they break and the ice melts. Liquid water does not necessarily have all four hydrogen bonds
Even though, there are higher heat temperatures surrounding the ice, its temperature doesn’t change in a solid state. Rudolf Clausius, a German physicist and mathematician, born in 1822, would further develop Mr. Carnot theory of heat and motion. He introduced strict principles of the second law of thermodynamics, which explains that the internal state of a system, in this case the ice cube, and the external state, the water, will eventually reach equilibrium. “Every force tends to give motion to the body on which it acts; but it may be prevented from doing so by other opposing forces, so that equilibrium results, and the body remains at rest.” (Hmolpedia Rudolf Clausius, Website). In other words, is that equilibrium is a direct result of the forces of motion acting on each of the bodies. Therefore, even if the ice is not subjected to melting temperatures, because of heat motion, equilibrium will eventually happen. Moreover, with this perception in mind, Mr. Clausius also expanded on thermodynamics and indicated due to constant disarray of elements; entropy is the ideal state that the universe will eventually reach. In short, he states that all natural events happening around us are contributing to a universal chaos. Subsequently, Rudolf Clausius supported the idea that the universe also acted as a whole and all the events happenings after
When the water in food forms ice crystals that will break down the cell structure, this can affect the texture of the food. Texture all depends on water content and treatment of the food that is being frozen. Blanching and using syrup help to protect the texture of some foods