INTRODUCTION
Gypsum is scientifically named calcium sulfate dehydrate with the formula (CaSO4.2H2O). It is known to be a white powdery substance that is a naturally occurring mineral. The main form of calcium sulfate dehydrate used in dentistry is named calcium sulfate hemihydrate with the formula (CaSO4)2.H2O. Gypsum is mainly used for dental restorations and applications to replicate the patients’ oral cavity. Dies and models are created using the 5 gypsum products; impression plaster (Type 1), model plaster (Type 2), dental stone (Type 3), dental stone with high strength and low expansion (Type 4) and dental stone with high strength and high expansion (Type 5). In dentistry the gypsum products that are being used are chemically similar
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However it is porous and also it has got irregular shape. Dental Stone (Type III)
Dehydration of gypsum under pressure in 125 degrees Celsius produces dental stone. This form of hemihydrate is called α-calcium sulfate. The powder particles of stone are much more regular (uniformed) in shape and it has higher density compared to model plaster. Dental Stone with High Strength and Low Expansion (Type IV)
After accomplishment of dehydration, another chemical such as 30% calcium chloride or magnesium chloride is added whilst boiling of gypsum product. The chlorides are later washed with hot water and since the solubilities of the hemihydrate and water are the same, it does not go into forming calcium sulfate dihydrate in presence of hot water. Furthermore, the powder that has been given out is the densest of all the gypsum types. Dental Stone with High Strength and High Expansion (Type V)
The production of dental stone with high strength and high expansion is the same as type IV production. However they do differ in the way that type IV contains extra salts and therefore has reduced expansion during
Basalt is mostly composed of augite, plagioclase and olivine. Augite comes in many shapes – cylinder, square, rectangular - but is usually rough and grayish black. Plagioclase is whitish brown and usually has a cubic shape with ragged edges. Olivine can be green, yellow or brown. It is usually three dimensional and octagonal.
Is dark blue color color going to grayish black . 2nd in commercial value is pyrolusite. This mineral is thought to have been deposited by ground water carrying manganese.
Its composition consists of Half Dome Granodiorite, which consists of quartz, feldspar, hornblende, and
It can also be seen through the ground water. As the ground water loses carbon dioxide, the water will become less acidic, causing the travertine to be deposited. The most prevalent form of travertine is in the form of flowstone. Flowstone is formed whenever water flows over boulders or ledges and creates layers of travertine. These flowstones usually can be seen in different earthy colors due to the impurities and the clear to white calcite
In the lab, the theoretical yield of CO2 was calculated by using the mass of the Alka-Seltzer (in Part A) and the mass of the anti-acid (Part B) were multiplied by the mole ratios that were involved in the reaction equation for each reaction and they were also divided by the molar mass of each substance. From the balanced chemical equations that were included in the calculation portion, the limiting reactant in part A was determined to be citric acid. The limiting reactant in part B was determined to be HCl because in the reaction, the HCl would ran out before the calcium carbonate. The stoichiometry would not have been different when converting between the different states of matter because the state is a measure of kinetic energy, and not
The methacrylate based, light cured, unfilled resin is perfect for filling small voids in the restoration. It gives the restoration a great seal which prevents any future leakage or failure. Before placing Permaseal, the restoration must be etched using the same phosphoric acid used earlier. After placing a thin layer, it is polymerized using the curing light and finally polished. The other two occlusal preps were similarly restored.
One difference between them is
Works Cited “Dentistry in the Elizabethan Era.” Interview by Brandi E. Brock. Elizabethan England: life in Elizabethan London n.d.: 66-67. Print. “Dentistry in elizabethan Time-Tooth enamel.”
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.
Finding the empirical formula for hydrated copper sulfate using calculations to find the amount of each element present in the copper ion, sulfate ion, and water while also comparing the empirical formula to a literature value. Christian Cooper Alexis Powers CHM1210-18M/Gregory Bowers 11-5-15 Purpose: To begin, there are several different goals, techniques, and claims to note in the experiment involving hydrated copper sulfate. The overall goal of this experiment is to find the empirical formula and compare it with a literature value. Yet, in finding the empirical formula of hydrated copper sulfate, there are several process for it to get through, like finding the percentages of copper, water, and finally sulfate.
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
CLAIRE MUNTING 29/01/2018 Criterion C EFFECTS OF SURFACE AREA OF CALCIUM CARBONATE UPON RATE OF REACTION Calcium Carbonate Chips 1 Introduction: Within the current investigation, the effects of the surface area of Calcium Carbonate (CaCO3) in combination with Hydrochloric acid (HCl) upon its rate of reaction. CaCO3, commonly referred to as limestone, is an organic substance and is, in a sense, the crystallised “carbonic salt” of the element, calcium2. In addition to being a salt, the pH level of Calcium Carbonate is 9.91, and it is therefore, a basic substance, due to the fact that it is comprised of a pH level higher than 7, which is neutral3. HCl, however, is the bodily acid found in the stomach of human beings.
The pozzolanas include Al2O3, SiO2, and Fe2O3. The cementitious material formed is known as calcium silicate hydrate, with a gel texture or calcium aluminate hydrate, with a fibrous texture. The pozzolanic reactions are illustrated as below in Figure 2.10. Figure 2.10: The pozzolanic reactions of fly ash The chemical composition of the fly ash is dependent on the features and configuration of the coal burned at the electric power generation facilities.
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.
Marble is calcium Carbonate (caCO3). 1- Calsium, 1-Carbon, 3-Oxygen{} cleaner product 4 Color of Marbles The impurities present in the limestone during re-crystallization give marble wide variety of colors. The purest calcite marble is white