Furthermore, the large number of products, with wide variations in unit costs, could lead to inaccurate amounts. | The auditor will likely focus extensively on inventory management controls to determine the effectiveness of those controls in the prevention of theft. The auditor may also engage a pharmaceutical specialist to assist with the identification and evaluation of various medicines as part of the
It is insoluble in water. From these properties it can be identified as miraculous bromide, Hg2Br2. The equation for the reaction would look like this: Hg + Br2 → Hg2Br2 (1) Discussion 2 * Identify the two important classes of
By, solving the system of equations using linear algebra, the concentrations of the indicator and the conjugate base were determined. The Henderson-Hasselbach equation predicted that the pH for these solution plotted against the log of the ratio of the two species would yield a line whose Y-intercept equaled the pKa for methyl red. The value obtained was 4.96(1), which has a percent error of 1.9. Perhaps, if this were corrected for temperature there would be even greater agreement with the accepted value. INTRODUCTION The purpose of this experiment was to determine the pKa of an acid-base indicator (methyl red).
that are present in a sample, by generally observing the physical and chemical properties of the sample when they react with compounds with known reagents. After qualitative analysis has positively confirmed the presence of a particular element, ion, or compound, the amount of the substance can then be quantitatively determined through careful measurement (Barezzaghi, 2007). The qualitative detection of particular ions that are dissociated in a solution is dependent on the observed physical and chemical properties that result when the unknown ions react with a specific analyzing reagent with a known outcome. This qualitative method involves testing small samples of the unknown with different unique
The solubility of solids in a solvent is very dependent on temperature. A solid tends to be more soluble in hot solvents than in cold. This is the reason the crystals precipitate out when the solution is cooled. There are no ideal solvents, however there are a few traits to look for when choosing the best solvent. Those that will dissolve the solute when the solution is hot but not cold.
Introduction A titration was carried out in this experiment to find the concentration of hydrochloric acid is an unknown solution. The aim of this experiment is to determine the number of moles of sodium hydroxide in hydrochloric acid and then to determine the number of moles of sodium hydroxide present in gastric juices. Titration, or volumetric analysis, is a common laboratory procedure for the analysis of substances and solutions. In a titration, the analyst determines the volume of a solution, called a titrant, that reacts exactly with a known weight or volume of another substance. This reaction is carried out by adding a solution of reactant hydrochloric acid from a burette to a solution of sodium hydroxide until just sufficient of hydrochloric acid has been added to react with all of the sodium hydroxide.
At this point the volume of base used to neutralized the acid can be determined. Phenolphthalein is the indicator which is colorless in an acid but changes to a faint and permanent pink color in base. The purpose of this experiment is to prepare a sample for titration with a base, become familiar with a buret while using proper titration technique in reaching an end point. Hypothesis : If I titrate a base of known concentration with an acid of unknown concentration then I can determine the concentration can be calculated because of the titration calculation. Materials : • Vinegar • Two small beakers (150mL) • 250-mL Erlenmeyer flask • 10-mL graduated cylinder • 50-mL buret • Buret clamp • Small funnel • M NaOH Hazards : • Chemical spill • Broken glass
Bases are solutions that have too many OH- ions. Strong acids are known as having low pH levels on the pH scale, between 0-6 on the pH scale. Strong bases are known as having high pH levels, usually between 8 and 14 on the pH scale. Weak acids and weak bases have pH levels close to the middle of the pH scale; seven is considered neutral. Properties of Acids Taste sour (don't taste them!)...
Discussion: Based on the data collected, there are some inaccuracies within the calculated data points. Based on the calculations, ceramic is the best calorimeter and plastic is the worst calorimeter. At first glance this seems reasonable, however, the calculated calorimeter constant for plastic was negative, which is highly unlikely correct because this suggests that plastic absorbed all the heat from the system, rather than acting as an insulator for the system. In addition, the calorimeter constant for ceramic was calculated to be 87.3 J/C, which was abnormally high compared to the rest of the materials. Styrofoam is the next best calorimeter after ceramic, which makes a good amount of sense except that it is more than 70 J/C behind the calorimeter constant for ceramic.
Manufacturers of soft drink commonly used benzoic acid or sodium benzoate as food preservatives. Non diet soft drinks lack aspartame, a sugar substitute used in diet soft drinks. Benzoic acid is converted into its salt sodium benzoate through neutralization with sodium hydroxide. Sodium benzoate is rather used than benzoic acid as anti-microbial agent in food and beverages because of the solubility effect. Sodium benzoate is approximately 200 times more soluble than benzoic acid.