than the weight of the crude caffeine. Explain why the percent recovery is frequently low. • Crude caffeine contains contaminants‚ such as organic compounds‚ while purified caffeine is just pure caffeine. Therefore‚ the weight of the crude caffeine is more than the purified caffeine because of the additional contaminants adds weight. Since there are no additional contaminants to the purified caffeine‚ the percent recovery would be low. The percent recovery would also be low since the caffeine is pure
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+ 2 NH4+ + S2- Ag2S(s) + 2 NH4+ + 2 NO3- AP Chemistry Name _________________________________ Period ___ Date __/__/__ 4 Reactions in Aqueous Solution Acid-Base & Gas Forming Equations Solutions of Strong Acids & Strong Bases 1. Solutions of hydrochloric acid and barium hydroxide are mixed. 2 HCl + Ba(OH)2 BaCl2 + 2 H2O 2 H+ + 2 Cl-
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Acid rain is a rain or any other form of precipitation that is unusually acidic‚ i.e. elevated levels of hydrogen ions (low pH). It can have harmful effects on plants‚ aquatic animals‚ and infrastructure through the process of wet deposition. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxides which react with the water molecules in the atmosphere to produce acids. Governments have made efforts since the 1970s to reduce the release of sulfur dioxide into the atmosphere with positive
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[pic] |THE MECHANISM FOR THE ACID CATALYSED HYDROLYSIS OF ESTERS | | | |This page looks in detail at the mechanism for the hydrolysis of esters in the presence of a dilute acid | |(such as hydrochloric acid or sulphuric acid) acting as the catalyst. It uses ethyl ethanoate as a typical| |ester.
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Acid-base titration Aim To study the titration curve of a strong base-strong acid‚ strong base-weak acid and weak acid-strong base titrations Introduction Acid-base titrations are based on the neutralization reaction between the analyte and an acidic or basic titrant. When an acid and a base are present in a stoichiometric amount e.g. 1 mole HCl added to 1 mole NaOH‚ this means that the equivalent point has been reached in an acid-base system. The end point of an acid-base titration can be
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Sodium thiosulfate is safe to handle and store‚ but if it is mixed with an acid‚ a reaction happens. When dilute sodium thiosulfate is mixed with an acid‚ solid sulphur is made‚ which makes the solution appear cloudy. The reaction also makes small amounts of toxic sulphur dioxide gas. You will choose one factor and investigate this factor’s effect on the rate of reaction between sodium thiosulfate and dilute hydrochloric acid. A colorimeter is a device used in colorimetry that generally refers to
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Acid-Base Titration Objectives: 1. To titrate a hydrochloric acid solution of unknown concentration with standardized 0.10M sodium hydroxide. 2. To utilize the titration data to calculate the molarity of the hydrochloric acid. Materials: See handout for more info. Procedure: See handout for more info. Data and Calculations: Table 1: Volume of NaOH Required to Neutralize 10.00mL of Unknown HCl Molarity of NaOh | Trial 1 | Trial 2 | Trial 3 | Trial 4 | Initial Volume of NaOH(mL)
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Acid/ Base Titration Lab Design III Materials: Goggles HCl NaOH Distilled Water Label Beaker Graduated Cylinder Pipet Stirring rod Buret with clamp Stopper Ring Stand Utility Clamp Computer Computer Program pH probe Procedure: 1) 2) Goggles were put on. 3) 0.1 M NaOH solution was made using 0.4 g NaOH and 100 mL distilled water. The ingredients were added together in a beaker and stirred. 4) The buret was standardized by adding 10 mL of distilled water‚ rolling
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Synthesis and Purification of Acetylsalicylic Acid (ASA or Aspirin) Background Salicylic acid is a phenol as well as a carboxylic acid. It can therefore undergo two different types of esterification reactions‚ creating an ester either with the hydroxyl or with the acid. In the presence of acetic anhydride‚ acetylsalicylic acid (aspirin or ASA) is formed. Correspondingly‚ an excess of methanol will form methyl salicylate‚ which is also an analgesic. In this experiment‚ we shall use
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Vitamin C Introduction: The lab consists in determining the vitamin C concentration in a solution by a redox titration using iodine. Vitamin C (ascorbic acid) is a water-soluble‚ essential oxidant that plays a vital role in the protection of the body from infections and disease it is acquired from primary fruits and vegetables. With the use of different materials as natural orange juice‚ Tampico (chemical orange juice) and other solutions that contain vitamin C we will find the amount of vitamin
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