...Introduction Buffer is a solution that resists a change in pH when bases or acid are added. Solutions that are acidic contain high concentrations of hydrogen ions (H+) and have pH values less than seven. Buffer usually consist of a weak acid, and its conjugate base or a weak base and its conjugate acid. The function of buffer is to resist the changes in hydrogen ion concentration as a result of internal and environmental factor. This buffer experiment is important so that we relies the important of buffer in our life. Besides that, it is also important so that we master the buffer preparation techniques and can conduct the experiment ourselves without anyone to instruct us. Other than that, we got to learn how to operate a pH meter and we...
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...has a specific active site where the substrates attach. Many factors can affect enzyme activity such as temperature, pH, and the presence of inhibitors (John W. Kimball, 2014). The purpose of this lab was to examine factors affecting the enzyme function of peroxidase. In the 19th century French chemist Louis Jacques discovered catalysts. Catalysts are substances that enable a chemical reaction without participating in it, which led to specifically peroxidases. The structure of peroxidase is a very large enzymatic protein, and has complex molecules with complicated shapes involving multiple folding’s. The activity of peroxidase is dependent on pH. It exhibits maximum activity at a pH between 6.5 and 7.0. The activity of the enzyme is reduced when pH levels are increased. Peroxidase promotes the oxidation of various compounds naturally of peroxides, where hydrogen peroxide is reduced to form water (Wikimedia Foundation, 2015). Also peroxidases break compounds down into harmless substances by adding donor molecules. During this lab, the donor molecule used was guaiacol. Guaiacol was used because it changes color after hydrogens are lost. Peroxidase can use a wide variety of donor molecules, and reduce a wide range of peroxides. Peroxidase is found in plants to help minimize damage caused by stress factors. In the lab four stress factors are used, temperature, pH, boiling, and the inhibitor hydroxylamine. Stress factors...
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...Lynne Andrew NB 1110 / M 5 – 7:50 Lab 1 February 2, 2015 pH and Buffer – Using Red Cabbage Indicator to Measure pH Introduction This experiment was performed to evaluate the following hypothesis: Red cabbage indicator can be used as a measure of pH. According to Campbell, et al, in Biology: Concepts and Connections, red cabbage contains a water-soluble pigment called anthocyanin that changes color when it is mixed with an acid or a base. The pigment turns red in acidic environments with a pH less than 7 and the pigment turns bluish-green in alkaline (basic) environments with a pH greater than 7 (2012). The pH indicating property of red cabbage indicator is well accepted in the scientific community and is a useful standard for us to become familiar with. As stated in the lab text, having a known set of standards is important to gaining information about unknowns (2011). Red cabbage contains high levels of anthocyanins, which give the cabbage its deep purple hue. The pigments also change in relation to changes in pH, according to the lab text (2011). According to a University College London lab experiment titled Red Cabbage pH Indicator, with most pH indicators, the compound gains a proton at low pH (lots of H+) but loses it at higher pH. Although this may seem a slight change, it is enough to alter the wavelengths of light reflected by the compound. As a result, we see the color change with respect to pH. The lab description continues to state anthocyanins have...
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...Temperature, pH, Enzyme Concentration , and Substrate Concentration on Catecholase Introduction Enzymes are biological proteins that speed up the reaction rate of a chemical reaction. They work in the human body by lowering activation energy making certain that reactions will initiate. For every action, there is an equal and opposite reaction. In this case, factors that influence the activity of an enzyme are called modulators. If modulators activate enzymes the reaction rate catalyzed will significantly increase, but if the modulator inactivates enzymes the reaction rate catalyzed will significantly decreased (Silverthorn, 2004). The potentially disastrous influence of temperature, pH, enzyme concentration, and substrate concentration on enzymes and other proteins is one reason why these modulators are very strictly regulated by the body (Silverthorn, 2004). Temperature, a measure of the intensity of heat, is an important factor in the activity of enzymes. The velocity of an enzymatic reaction is influenced by temperature. This is because substrates collide with active sites frequently in the presence of rapidly moving molecules. In addition, although these molecules do move rapidly the speed of the reaction drops sharply. In short, thermal agitation causes protein molecules (enzymes) to denature ( breakdown of protein structures). All enzymes have an optimal temperature at which reaction rates go fastest without denaturing the enzyme (Campbell and Reece, 2002) pH, a measure...
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...Acids, Bases, PH Introduction. This experiment helped to understand difference between acid and base and there PH levels. We learned how to identify buffer. Buffer is substances that resist changes in PH when acid or base is added to solution. Also we learned that water is neutral. Its mean that water has an equal concentration of H and OH. PH number of water is 7. Acid’s PH numbers less than 7. Bases’ PH number is greater than 7. As well we learned how to use and calibrate PH Meter. Materials and methods. For experiment at class we used two solutions, solution A and solution B. First we took PH meter and measured PH level of solution A. After we add to solution A 1.0ml of HCl and record PH level. Total of HCl added was 10 ml, we did it by adding 1.0 ml of HCl at the time. Second time we took solution A and start adding 10 ml(1.0 ml at the time) of NaOH. With PH meter we record number changing in PH. Third time we took solution B , measured PH level and did the same steps as with solution A. Results. Solution A. ml of acid or base added 1 2 3 4 5 6 7 8 9 10 HCl 6.95 6.91 6.92 6.93 6.91 6.90 6.88 6.88 6.87 6.88 NaOH 6.99 6.99 7.02 7.01 7.02 7.01 7.02 7.03 7.06 7.07 Solution B. ml of acid or base added...
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...Effect of Temperature on Rate of Reaction of Catalase Abstract Properties of Enzymes focused on the variations of reaction rates amongst enzymes subjected to various circumstances such as temperature, pH levels, different concentrations of substrate, salt concentrations, Metal Copper Sulfate and lastly, the presence of an Enzyme Inhibitor. The assigned section of this laboratory for our efforts was the effect of temperature variations on enzyme reactions. To perform the experiment, we used a spectrophotometer to monitor the baseline catalase activity when they are placed in these two temperatures. In this way, absorbance can be measured over time to monitor catalase activity of the main baseline reaction. Our results showed that temperatures at higher degrees led to being inactive, whereas those at lower degrees lowered the reaction time. This comes to show that each enzyme can have a different optimal temperature and this experiment helped us to understand how reaction rate can be affected by temperature change. Introduction Thousands of complex biological processes are constantly taking place within our bodies. We require material transport, energy synthesis, and the manufacturing of various proteins, hormones, and other molecules (Source 1). Almost all of these everyday processes rely on the function of enzymes to take place. Enzymes are specifically grouped according to their function, and this information can often provide us with clues regarding what type of reaction...
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...side analysis of the reactivity test in which Hydrochloric acid (HCI), lead nitrate (Pb(NO3)2) and sodium hydroxide (NaOH) was added to three separate samples of the compounds unknown #1 and #11 aqueous solutions. The results for both unknowns were identical, leading to the conclusion that my unknown solid #11 was the same unknown solid as #1. Introduction When conducting research it is important to be comfortable communicating your results with other researchers so that they can be further analyzed and compared with the results of other research experiments. Another large part of conducting research is to be comfortable determining, describing and comparing chemical and physical properties of compounds. Many compounds can look very similar, but have drastically different chemical properties, so it is important to know which tests can be performed on a compound to help determine what it is, or what it is not. In this experiment 2 sets of six unknown solid compounds were put into small jars and labeled with the numbers 1-12, numbers 4, 6 and 8 were not used. Each lab group was given one unknown solid and told to determine the samples properties through various testing. Physical characteristics were observed, by using a magnifying glass to view a small amount of the sample. Relative solubility was found by mixing a small amount of the unknown solid with deionized water. Electrical conductivity was measured by using a conductivity meter and noting the amount of bars on the...
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...Experiment 5, CH-201-051 Lab Date: 1/28/15 Due Date: 2/4/15 Dr. Paliwal Acid-Base Reactions Purpose: The purpose of this set of laboratory experiments is to study the correlation between acids and bases by measuring and comparing their pH level. This can then be used to further evaluate the neutralization of acids with a base, such as stomach acid with calcium carbonate, antacid tablets. Data: Part B-1: Test pH of Laboratory Chemical Solutions Name Chemical Formula Calculated pH of 0.010 M Solution Laboratory pH Test results (0.010 M) Sodium Chloride NaCl 7 7.07 Ammonia 〖NH〗_3 10.62 10.15 Sodium Acetate 〖NaCH〗_3 〖CO〗_2 8.88 7.24 Hydrochloric Acid HCl 2.0 1.71 Ammonium Chloride 〖NH〗_4 Cl 5.63 6.58 Acetic Acid 〖CH〗_3 〖CO〗_2 H 3.38 3.33 Sodium Hydroxide, Lye, or Caustic Soda NaOH 12.0 11.68 Ammonium Acetate 〖NH〗_4 〖CH〗_3 〖CO〗_2 7.0 7.69 Part B-2: Test pH of paired Acid and Base solutions: Compound Names Compound Formulas Measured pH of Equal volumes of Solutions Hydrochloric Acid + Sodium Hydroxide HCl+NaOH 4.58 Ammonia + Acetic Acid 〖NH〗_3+〖CH〗_3 〖CO〗_2 H 9.05 Part B-3: Test pH of common Household items Household Item Name: Test pH: Lemon Juice 2.07 Ammonia 11.53 Mouth Wash 4.04 Vinegar 2.02 Part C- Testing Effectiveness of Antacids Acid Solution Antacid Test #1 pH result Test #2 pH result Diluted 20 mL of HCl solution to simulate Stomach Acidity none 2.45 Control Value 2.45 Control Value Diluted...
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...as well as the plants and crops that the farmers grow. 2. What factors apart from acid rain could be killing trees? Oil spills, areas experiencing droughts, trash and litter, and human beings. 3. Limestone, an underlying material for many soils, dissolves and corrodes when exposed to high concentrations of hydrogen ions. How is this information important in understanding the effects of acid precipitation? Because when the limestone corrodes it produces hydrogen ions; therefore, when it rains, fogs, or snows it causes a more acidic solution to form in the soil, thus, causing more damage to the soil by removing its nutrients. 4. Acid precipitation is considered severe if it falls below pH 4. Considering the pH of rainwater, how easy would it be to convert the rainwater to acid precipitation? It would be extremely easy, being...
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...29 EXPERIMENT 3. ACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND Carbonate Equilibria In this experiment a solution of hydrochloric acid is prepared, standardized against pure sodium carbonate, and used to determine the percentage of carbonate in a sample. An aqueous solution of hydrochloric acid is almost completely dissociated into hydrated protons and chloride ions. Therefore, in a titration with hydrochloric acid the active titrant species is the hydrated proton. This species is often written H3O+, although the actual form in solution is more correctly (H2O)nH+. For convenience we designate it simply H+. Carbonate in aqueous solution acts as a base; that is, it is able to accept a proton to form bicarbonate ion. 2CO3 + H+ HCO3 (1) Bicarbonate is able to combine with another proton to form carbonic acid: HCO3 + H+ H2CO3 (2) Equilibrium expressions for the dissociation of bicarbonate and carbonic acid may be written 2[H+] [CO3 ] K2 = (3) [HCO3] [H+] [HCO3] [H2CO3] and K1 = (4) 30 where K1 and K2 are the first and second acid dissociation constants for H2CO3; the experimentally determined values are K1 = 3.5 x 10-7 and K2 = 5 x 10-11. When successive protonation reactions such as (1) and (2) occur, the extent to which the first reaction proceeds before the second begins depends on the difference between the two acid dissociation constants. By combination of Equations (3) and (4) with those for charge and...
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...rate of almost all the chemical reactions which take place in living organisms. The rate of enzymes activity is influenced by temperature, pH, and substrate concentration. The purpose of this lab was to determine the affects of enzyme activity under specific temperature changes, pH values and substrate concentration. Since heat increases the rate of most chemical reactions, the addition of heat causes faster molecular movement. Most enzymes active in living tissue becomes denatured, their secondary or tertiary protein structure breaks down, at the temperature above 40 degrees C. In the effects of pH, it is expected that the changes in pH would have an effect on the action of enzymes. Lemon juice helps keep the apple from growing, because its full of ascorbic acid (Vitamin C) and it has a low acidic pH level. But extreme high levels of low pH values can result in a complete loss of enzymes activity thus leaving the apple to brown. The effects of substrate concentration, an enzyme substrate complex is formed when a substrate fits into active of an enzyme. The velocity, the rate of speed, at which the enzymes works will increase until it reaches a maximum. If the substrate is present in excess amounts, the reaction rate will increase enzyme concentrate, so that the available substrate does not limit the rate of reaction. In the experiment the Independent Variable was the temperatures of A and B. A being body temperature of 37 degrees. And B being ICE water 7 degrees Celsius...
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...The Scientific Method with Lifesavers Lab Report Paul McPhee Lab1 Professor Stanley Aviron Performed September, 2013 Submitted September 2013 Introduction Candy is great and has been around for many years. I don’t know anyone that hasn’t tried candy of some sort at least once. There are a very many categories of candy but we will look at “ sweet, hard candy”, specifically the Lifesaver for this experiment. Food is chewed/dissolved or more simply, broken down into smaller parts before consumed. Lifesavers are food but are seldom chewed, yet they breakdown into smaller pieces or before ingested. Lifesavers are dissolved in the mouth over a relatively short period of time. Why do they dissolve? At what rate do they dissolve and is this rate the same for all people? Lifesavers are made-up of mostly sugar and artificial ingredients. Regardless, it is likely that higher acidic substances will dissolve the candy faster than lower acidic substances. Materials and Methods Firstly, we as a group, spent time applying our senses to the lifesaver and recorded out thoughts. It is a relatively light but solid candy, round with whole in its middle. In my case it was red and smelled fruity and fragrant but unlike real, organic fruit or flowers. It tasted great and I enjoyed the experience very much. It took about five minutes to completely dissolve the candy in my mouth. Since saliva is different from depending on persons mouth, it was decided to apply...
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...AIM: Aim of the experiment is to investigate and analyse the effect of pH on the transfer of salicylate across membranes. INTRODUCTION: As Schedule METHOD: As Schedule RESULTS: Test Tube number | Absorbance | 1 | 0 | 2 | 0.171 | 3 | 0.337 | 4 | 0.496 | 5 | 0.598 | 6 | 0.801 | 7 | 1.598 | 8a | 0.46 | 9a | 0.629 | 10a | 0.701 | 11a | 0.899 | 8b | 0.704 | 9b | 0.793 | 10b | 0.830 | 11b | 0.877 | 1. 1.0 x (PCV/100)X0.9= Volume of yeast The PCV= 18% :. 1.0x (18/100)x 0.9 = VY Vy= 0.162 2. Total volume- yeast volume= volume of supernatant :. 3.0ml- 0.162 = 2.838 3. Concentration of salicylate | Sal.concentration | V.S x C.S | Amount of sal. In yeast cells | Conc of sal. Inside yeast | 1 | 0 | 0 | 0 | 0 | 2 | 0.1 | 0.2838 | 1.7162 | 10.59 | 3 | 0.2 | 0.5876 | 1.4324 | 8.84 | 4 | 0.3 | 0.8514 | 1.1486 | 7.09 | 4 | 0.4 | 1.1352 | 0.8648 | 5.34 | 6 | 0.5 | 1.419 | 0.581 | 3.59 | 7 | 1.0 | 2.838 | -0.838 | 5.17 | 4. Volume of supernatant x concentration of salicylate :. 0 x2.838 = 0 0.1 x 0.2838 = 0.2838 0.2 x 0.2383 =0.5876 0.3 x 0.2383 = 0.8514 0.4 x 0.2383 = 1.1352 0.5 x 0.2383 = 1.419 0.6 x 0.2383 = 2.838 5. Amount of salicylate in yeast cells= 2mg-amount of salicylate in supernatant 2mg. ( Please refer to table 2) 6. Concentration of salicylate inside yeast = amount of sal./ V.Y (Please refer to table 2). 7. PH = PKa + log(salt/acid)...
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...Write your name here Surname Other names Centre Number Candidate Number Edexcel GCE Chemistry Advanced Unit 4: General Principles of Chemistry I – Rates, Equilibria and Further Organic Chemistry (including synoptic assessment) Monday 14 January 2013 – Afternoon Time: 1 hour 40 minutes You must have: Data Booklet Candidates may use a calculator. Paper Reference 6CH04/01 Total Marks Instructions Use black ink or ball-point pen. Fill in the boxes at the top of this page with your name, centre number and candidate number. Answer all questions. Answer the questions in the spaces provided – there may be more space than you need. Information The total mark for this paper is 90. The marks for each question are shown in brackets – use this as a guide as to how much time to spend on each question. Questions labelled with an asterisk (*) are ones where the quality of your written communication will be assessed – you should take particular care with your spelling, punctuation and grammar, as well as the clarity of expression, on these questions. A Periodic Table is printed on the back cover of this paper. Advice Read each question carefully before you start to answer it. Keep an eye on the time. Try to answer every question. Check your answers if you have time at the end. Turn over P41214A ©2013 Pearson Education Ltd. *P41214A0128* 7/6/5/5/4/ SECTION A Answer ALL the questions in this section. You should aim to spend no more than 20 minutes...
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...EDUCATIONAL SERVICES 12-A/2, Yusuf Sarai N.D. 16 Ph.: 65643449, 9810004225 www.eeducationalservices.com Chapter – 2 Acids, Bases and Salts Q 1. You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper; how will you identify the contents of each test tube? Ans. Dip fresh red litmus paper separately in three test tubes. The solution in which it turns red litmus to blue litmus contains basic solution. The blue litmus paper formed here can now be used to test the acidic solution. Now, put the blue litmus paper in the remaining two test tubes. The solution in which it turns blue litmus paper to red contains acidic solution. The solution which has no effect on any litmus paper contains distilled water. Q 2. Why should curd and sour substances not be kept in brass and copper vessels. Ans. Curd and sour substances contains acids which react with brass and copper vessels. Because of this, the food becomes unfit for eating. Also, produced acid, corrodes the brass and copper. Q 3. Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test...
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