Discussion The ideal Van't Hoff factor for potassium chloride is 2, because the compound dissociates into its ions, K+ and Cl-. The greater the Van't Hoff factor means the more a compound lowers the freezing point temperature of the solvent it dissolves in. For a liquid to freeze it must form a lattice, a three-dimensional arrangement of particles that make up a crystalline solid, and the presence of solute particles interferes with the ability of the solvent particles to form a lattice. To compensate the system must be brought to an even lower temperature to freeze, and the more particles that are present within the solvent, the larger that freezing point depression becomes.3 Thus, the obtained value of 2.05 means that potassium chloride lowered …show more content…
This was displayed in table 1, where the final temperatures of the water are lower compared to the initial temperatures, showing that the potassium chloride took heat energy away from the 20 mL of water. Endothermic deicers work slower than exothermic deicers, because endothermic deicers require warmer temperatures to dissolve, which makes them inferior when environmental temperatures are very low. Additionally, exothermic deicers will release energy as heat when the compounds dissociate, consequently, melting snow and ice faster.4 Furthermore, when comparing the enthalpy of dissolution of potassium chloride to magnesium chlorides value of -270, the most exothermic value in table 2, potassium chloride is shown to be a significantly worse deicer. Magnesium chloride being notably exothermic means that the compound can dissolve at low temperatures and releases copious amounts of heat …show more content…
The enthalpy of dissolution for potassium chloride came out to be 8.73 kJ/mol, which indicates that the process was endothermic. Since the dissociation of potassium chloride is endothermic, it requires heat to dissolve, which makes it a low preforming deicer in very cold temperatures. Potassium chloride costs $8.99 per lb and compared to the lowest cost deicer sodium chloride, which costs $2.09 per lb, potassium chloride was not cost efficient. The environmental impacts are due to the chlorine component of each deicer. There are various negative health effects induced by chlorine that appear in animals and organisms in water and soil environments. However, all potential deicers have the same relative environmental impact. When all characteristics of the potential deicers are taken into consideration, the best road deicer was calcium
The design relied on two Schmitt triggers to generate the two different tones while using the transistors to act as a switch. This causes it to trigger continuously between two unstable states, allowing automatic switching between two frequencies producing two different tones. The RC values between the two Schmitt triggers will differ. Capacitors charge and discharge faster when it’s resistance is smaller.
Experiment 7 In this experiment we configured several DC circuits consisting of an emf and a network of resistors. The circuits were composed of a power supply, two DMMs, a circuit board, an SPST switch, and an assortment of known resistors along with one unknown resistor. We measured the current and voltage of the entire circuit as well as the potential drops across each resistor to determine the parameters of the circuit including the resistance, voltage, and current for each component.
In this lab we were trying to figure out if Salt Creek and Barker Lake had the correct chemical balances to sustain catfish for the years coming. In order to find this out, we tested the water using a Hach Water Testing Kit. Inside were dissolved oxygen reagent powder pillows 1, 2 and 3 which we added and mixed into our sample water to prepare it for testing. Then we added droplets of Sodium Thiosulphate Solution into the prepared water too see how much dissolved oxygen parts per million were in the water. Our independent variable in this experiment was the 5 different testing sites that we went to for water samples.
1. Identify the range of senses involved in communication • Sight (visual communication), Touch (tactile communication), Taste, Hearing (auditory communication), Smell (olfactory communication) 2. Identify the limited range of wavelengths and named parts of the electromagnetic spectrum detected by humans and compare this range with those of THREE other named vertebrates and TWO named invertebrates. Figure 1: the electromagnetic spectrum source: www.ces.fau.edu Vertebrates Human Japanese Dace Fish Rattlesnake Zebra Finch Part of electromagnetic spectrum detected ROYGBV (visible light) detected by light sensitive cells in the eye called rods and cones.
Purpose: The purpose of this experiment was to determine the molar mass of unknown #43 using the derived freezing point depression. To obtain the freezing point depression, t-butyl alcohol was placed in a cold-water bath and frozen solid for a total of two runs. Then, unknown #43 was dissolved in t-butyl alcohol and placed in a cold-water bath until frozen solid. This process was repeated for a total of three runs, with the first two runs containing half of the unknown, and the last run containing the full amount of unknown.
In this lab there were five different stations. For the first station we had to determine an unknown mass and the percent difference. To find the unknown mass we set up the equation Fleft*dleft = Fright*dright. We then substituted in the values (26.05 N * 41cm = 34cm * x N) and solved for Fright to get (320.5g). To determine the percent difference we used the formula Abs[((Value 1 - Value 2) / average of 1 & 2) * 100], substituted the values (Abs[((320.5 - 315.8) /
Tn 4351 was originally isolated from bacteroides fragilis [30] . The transposon was successfully introduced into Cytophaga succinicans, Flavobacterium meningosepticum, Flexibacter canadiansis, Flexibacter strain SFI and Sporocytophaga myxococcoides by conjugation [25]. Tn 4351carries two antibiotic resistance gene. One of the codes for resistance to erythromycin and clindamycin which is expressed in bactroides but not in E.Coli. The other gene codes for resistance in tetracycline and is expressed in aerobically grpwn E. coli, but not in anaerobically grpwn E. coli or in bacteroides.
The dissolution of the salt could be reversed by evaporating the water as shown in part one of the experiment, just as evaporating the water could be reversed by adding water as demonstrated in part two of the
Properties of Ionic and Covalent Substances Lab Report Introduction The purpose of this lab was to determine which of the following substances: wax, sugar, and salt, are an ionic compound and which are a covalent compound. In order to accurately digest the experiments results, research of definitions of each relating led to the following information: ionic compounds are positive and negatively charged ions that experience attraction to each other and pull together in a cluster of ionic bonds; they are the strongest compound, are separated in high temperatures, and can be separated by polar water molecules. A covalent compound forms when two or more nonmetal atoms share valence electrons; covalent compounds are also
Introduction: In this lab, of water in a hydrate, or a substance whose crystalline structure is bound to water molecules by weak bonds, is determined by heating up a small sample of it. By heating, the water of hydration, or bound water, is removed, leaving only what is called an anhydrous compound. Based on the percent water in the hydrate, it can be classified as one of three types: BaCl2O ⋅ 2H20, with a percent water of about 14.57%, CuSO4
℃^(-1)×6.40℃±3.1 %=1337.6 J±4.06 % ∆H=(-1337.6 J±4.06 %) /(0.025 mol ±0.16 %)= -53504 J m〖ol〗^(-1)±4.22 % ∆H=-53504 J m〖ol〗^(-1)±4.22 %÷1000=-54 kJ m〖ol〗^(-1)±4.22 % Conclusion and
Properties of Ionic and Covalent Substances Lab Report Introduction The purpose of this lab was to determine which of the following substances: wax, sugar, and salt, are an ionic compound and which are a covalent compound. In order to accurately digest the experiments results, definitions of each relating factor were researched, leading to the following information: ionic compounds are positive and negatively charged ions that experience attraction to each other and pull together in a cluster of ionic bonds; they are the strongest compound, are separated in high temperatures, and can be separated by polar water molecules. A covalent compound is formed when two or more nonmetal atoms share valence electrons; covalent compounds are also categorized into two sections: polar covalent and nonpolar covalent. Furthermore, polar covalent compounds dissolve in water, while nonpolar covalent compounds do not.
Introduction The goal of the experiment is to examine how the rate of reaction between Hydrochloric acid and Sodium thiosulphate is affected by altering the concentrations. The concentration of Sodium thiosulfate will be altered by adding deionised water and decreasing the amount of Sodium thiosulphate. Once the Sodium thiosulphate has been tested several times. The effect of concentration on the rate of reaction can be examined in this experiment.
Introduction Solubility is a chemical property that is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called saturated solution. For example when a sample of sodium chloride solution in water is heated the behavior of the reaction is endothermic obstructing exothermic behavior. Another relationship that can be said about solubility is that the solubility of a solid substance increases as the temperature increases. The solubility of solutes is dependent on temperature.
That is, the higher the temperature of the solvent (water), the more solute (salt) that will dissolve in it. In this experiment, we will study the solubility of potassium nitrate (KNO3) in water. You will dissolve different quantities of this salt in a given amount of water at a temperature close to its boiling point. Which solution will be