entropy‚ and standard free energy were established. II. THEORETICAL BACKGROUND The reaction that is studied in this experiment is the dissolution of borax in water. “Borax” is a naturally occurring compound; it is in fact the most important source of the element boron‚ and it has been used for many years as a water softening agent. Borax is a rather complicated ionic salt which has the chemical formula Na2B4O7•10H2O (Petrucci‚ 2007). When it dissolves‚ it dissociates as follows:
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dissolution of borax in water. In procedure one of the experiment‚ the temperature of the borax solution was varied and its saturation level was measured at different temperatures (10°‚ 30°‚ 40°‚ 50°). In procedure two‚ the concentration of the borate anion was measured through a titration with 1.00 M HCl. Equation 6: Ksp= [Na+]2 [[B4O5(OH)4]2-]= (s)(2s)2=
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EXPERIMENT 2 ACID DISSOCIATION CONSTANT OF AN INDICATOR DYE OBJECTIVES Using spectrophotometric method: determine the wavelengths at which the acid and base forms of the dye in aqueous medium exhibit maximum absorption; determine the molar absorptivities of the acid and base forms of the dye and estimate an unknown concentration of the dye in solution using the Beer-Lambert’s Law; and determine the acid dissociation constant of the indicator dye. THEORY The absorption or reflection of
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INTRODUCTION: Nowadys‚ indicators have become technologically advanced and can be used for the main purpose of indicating whether something is acidic‚ basic or neutral. This is possible because in solutions of different pH‚ the colour of the inidcator will change simultaneously with pH change. This is made possible by pigments in the indicators. Hand made indicators include universal indicator‚ methyl orange‚ phenolphthalein and many more. Acids and bases are diverse in this world. They are everywhere
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from a primary standard. Primary standard solutions are used in determining the concentrations of other solutions to an extremely high accuracy. They are typically used in titrations and other analysis techniques as standardization solutions. A secondary standard solution‚ such as HCl solution‚ is a solution which must be standardized first against a primary standard‚ but afterwards‚ it will be stable enough for titrimetric work (Titration). Titration involves the gradual addition of a solution of
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DATE: 2ND APRIL‚ 2009. AIM To prepare and standardize HCl solution. INTRODUCTION Standardization is a process of determining the relationship between the measured signal and the amount of analyte. Standardization can be defined also as a titration experiment in which the concentration of a solution becomes known to a high degree of precision and accuracy. In a standardization experiment‚ the solution being standardized is compared to a known standard. This known
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| Carbonate | CO3 | -2 | Nitrate | NO3 | -2 | Phosphate | PO4 | -3 | Hydrogen Carbonate | HCO3 | -1 | Acids and Bases in the Laboratory Back to Top Some common acids that are found in laboratories are Hydrochloric acid (HCl)‚ Sulphuric acid (H2SO4) and Nitric acid (HNO3). Some of the lesser used acids are Acetic acid (CH3COOH)‚ Hydrofluoric acid (HF)‚ Carbonic acid (H2CO3). Hydrofluoric acid is a highly corrosive acid and is used to etch glass. Some acids are found in
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acid-base reactions. Titrations are often used in industry to analyze products to be sold. In this lab‚ standardizations will be done in the first two experiments and then titration analysis in the third. Standardization of a base (NaOH) using a primary standard (KHP) Standardization of an acid (HCL) with the standard base Titration analysis of unknown acids and bases (antacid tablets) Standardization of NaOH Materials: -Buret -250 mL Erlenmeyer flask -0.1 M NaOH -0.8 g KHP -Water
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determine the weight % of Na2CO3 through the preparation of NaOH and HCl standards. The molarity of the standards will be found through titration of KHP for NaOH‚ HCl vs the known NaOH‚ and the unknown Soda Ash sample vs the known HCl. II. Equations and Sample Calculations: Titration of HCl with NaOH: Complete Equation: HCl (aq) + NaOH (aq) H2O (l) + NaCl (aq) Net Ionic Equation: H+ + OH- H2O(l) Calculations (10mL 0.1M HCL‚ 100mL H20‚ 7.8mL NaOH): # mols NaOH = 0.1M (known concentration)
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volumetric flask. In the second method‚ the solution is standardized by titrating - a weighed quantity of a primary standard a weighed quantity of a secondary standard or a measured volume of another standard solution. As a result‚ standardization is a process of determining the concentration of a substance in solution by adding to it a standard reagent of known concentration in carefully measured
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