...Practical 3 Investigation of Action of Saliva and Hydrochloric Acid in Two Carbohydrate Solutions ____________________________________________________________________________________ Objective: Students are expected to state the objective of this experiment. Apparatus & Equipments: Boiling tubes Metal test tube racks Beaker Graduated plastic dropper Water bath, ~ 37 oC Water bath, ~ 95oC Materials: Carbohydrate solution A Carbohydrate solution B Benedict’s solution 3 M Hydrochloric acid 3 M Sodium hydroxide Procedures: 1. Prepare two boiling tubes containing 1 ml solution A and 1 ml solution B respectively. Add 1 ml Benedict’s solution to each tube. Heat both tubes together in the (~95oC) water bath for two minutes. Record the results in table 1. 2. Add a few drops of fresh solution A and B separately spaced on a white tile. On each solution, add 1-2 drops of iodine solution. Mix with pen cover. Record your observations in the table 1. 3. Pipette 2 ml solution B into each of four boiling tubes. Label the tubes 1, 2, 3 and 4 respectively near mouth of tube. Label your group name. 4. Place tubes 1 and 2 in a water bath of ~37oC. (It doesn’t matter how long you put it in at this stage as no saliva or HCl have been added yet). 5. Salivate into a small beaker till it reaches about 5 ml. 6. Step (6) and (7) is to be done approximately at the same time. Measure out 4 ml of the saliva prepared in step (4) and pipette 2 ml each into tubes...
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...CONFIDENTIAL Employee Performance Evaluation Employee's Name _______________________________________Title __________________ Office/Dept. _________________________Date of Evaluation __________________________ PERFORMANCE DEFINITIONS *3 2 1 STEP I COMMENDABLE ACCEPTABLE MARGINAL Performs beyond specified requirements within job description Meets the specified requirements of job description Corrective action and/or release from job may be required EVALUATE THE ELEMENTS OF PERFORMANCE. Evaluate all factors indicated below by checking the appropriate space and commenting where applicable. *3 _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ 2 _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ 1 _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ QUALITY - Performs work thoroughly effectively accurately QUANTITY - Completes the necessary amount of work Is able to prioritize tasks KNOWLEDGE - Is capable in handling all phases and details within job specifications HUMAN RELATIONS - Is willing to work with others Is able to work with others COMMUNICATION SKILLS - Effectively presents written ideas and information to others JUDGEMENT - Is able to make decisions based on sound reasoning JOB DEPENDABILITY - Is honest and reliable in carrying out instructions _____ Observes Personnel Policies _____ Complies with established...
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...Practical 3 Investigation of Action of Saliva and Hydrochloric Acid in Two Carbohydrate Solution | Objective: 1. To show the action of saliva in two carbohydrate solutions. 2. To show the action of hydrochloric acid in two carbohydrate solutions. Apparatus & Equipment’s: Boiling tubes Metal test tube racks Beaker Graduated plastic dropper Water bath,~37°C Water bath,~95°C Stop watch Test tube holder Materials: Carbohydrate solution A Carbohydrate solution B Benedict’s solution 3M Hydrochloric acid 3M Sodium hydroxide Procedures: 1. Prepared two boiling tubes with containing 1 ml solution A and 1 ml solution B respectively. 1 ml Benedict’s solution was added to each tube and heated both tubes together in the (~95°C) water bath for two minutes. Then, recorded the results in table 1. 2. Added a few drops of fresh solution A and B separately spaced on a white tile. On each solution, added 1-2 drops of iodine solution and mixed with pen cover. Recorded your observations in the table 1. 3. Pipetted 2 ml solution B into each of four boiling tubes. The tubes were labelled 1, 2, 3 and 4 respectively near mouth of tube. Labelled your group name. 4. Placed tubes 1 and 2 in a water bath of ~37°C. 5. Salivated into a small beaker until it reached about 5 ml. 6. At the same time, step (6) and (7) was to be done approximately. Measured out 4 ml of the saliva prepared in step (4) and pipetted 2 ml each into tubes 1 and 4. The contents of the tubes shook well to ensure...
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...1. Advance Room Booking will be held as per the dates below. Same Room Booking – Female and Male Date | 23 - 26 June 2014 (Monday to Thursday) | Time | 8.30 am to 5.30 pm | Venue | Accommodation Office – (ACO) - Einstein Ground Floor | Residents are required to come to ACO to secure their rooms for the following semester during the Advance Room Booking period. Invoice collection will be from 30 June 2014 onwards at ACO. If you fail to do so during this time period your room will not be available for the following semester. If your roommate is graduating and or leaving the Halls of Residence you will need to find a new roommate. Please update ACO as soon as possible with the new roommate’s name. If you are unable to find a new roommate you will be required to fully check out from the room and ACO will reassign you to another room. When a room is totally empty the university is able to conduct preventive maintenance. There is storage space available. Boxes will be provided by ACO and you will need to return them 3 days after you check in. 2. Changing Room Policy Residents who wish to change rooms will only be considered on a ‘Case by Case Basis’ and ‘Subject to Room Availability’. Residents need to book back their same room during the Advance Room Booking period and to drop by ACO to complete an Appeal Form and submit it with a supporting letter from 1 - 2 July 2014. Only fully completed Appeal Forms with valid reasons will be considered. No appeal for change of...
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...Experiment 8. The hydrolysis of starch with hydrochloric acid (a) Prepare a water bath by half filling a 250 cm3 beaker with warm water and heating it to boiling point on a tripod and gauze, with a Bunsen burner. When the water boils, reduce the flame to keep the water at boiling point. (b) Label four test-tubes 1-4. (c) Copy the table given below into your notebook. (d) In each tube place 5 cm3 3% starch solution. (e) Using a syringe or graduated pipette, add 3 cm3 Benedict's solution to the starch solution in tube 1 and place the tube in the boiling water bath for five minutes. (f) Rinse the syringe or pipette and use it to add 1 cm3 dilute hydrochloric acid to the starch solution in each of tubes 2, 3 and 4. Note the time and place all three tubes in the water bath. (They will be removed at five, ten and fifteen minutes respectively). (g) Remember to remove tube 1 from the water bath after five minutes if you have not already done so. (h) After five minutes, remove tube 2 from the water bath and cool it under the tap. Neutralize the acid by adding solid sodium bicarbonate, a little at a time, until the addition of one portion produces no fizzing. Place tube in the rack and return to tube 3. (i) After ten minutes in the water bath, remove tube 3, cool and neutralize the contents as described in (h). Place the tube in the rack. (j) After fifteen minutes in the water bath, remove tube 4; cool and neutralize as before, and place it in the rack...
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...Laboratory Report The Rate of Reactions Abqari Afandi Grade 10 October 6th 2014 Purpose: To investigate the relationship between the temperatures of Hydrochloric acid with the duration of Magnesium ribbon to dissolve in the acid. Procedure: 1- Prepare four 400ml beaker: one for the hot bath, one for the room temperature, one for ice water bath and one for super hot bath. Fill all beakers half-full. Put one on a hot plate; the temperature of the water on the hot plate should not exceed 60C. Put another one on a hot plate; the temperature of water should not exceed 80C. Control the temperature of both hot plates to keep the temperature of water stays at 60C and 80C. 2- Using a graduated cylinder, add 20ml of 1M hydrochloric acid to each of the two test tubes, (all tubes should be the same size) 3- Place one test tube in the room temperature water, one test tube in the hot water bath, one in the ice water bath, and one in the super hot bath; allow the tubes to sit for approximately 5 minutes to reach thermal equilibrium. 4- Obtain a strip of magnesium ribbon (~16cm). Using scissors cut the ribbon into 4.0 strips. Be as precise as possible. 5- Wrap a piece of copper wire around a pencil to make a small ‘cage’ into which the magnesium ribbon will be inserted. The other end of the wire should be long enough so that the wire can hang over the side of the test tube with the cage submerged beneath the liquid level in the test tube. 6- Measure and...
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...done then you pour out 50c3,40cm3,30cm3,20cm3,10cm3 of the solution into five same conical flasks ,once this is done you then add water to the other conical flask in 50cm,make sure you label the flasks so that you know which one has so much concentration . 4. After this is done you must now take a beaker and add 35cm3 of concentration hydrochloric acid to 65cm3 of water to make a diluted solution 5. Now then take a piece of paper and draw a black cross on the paper , and the place one of the flasks on top of the paper , you must do one flask at a time using a measuring cylinder measure out 10cm3 of hydrochloric solution , and add this to the flask ,immediately stir the flask and start the stop watch. 6. Finally as soon as you can not see the cross anymore stop the stop watch and record the results in a table , repeat this with all the flasks The reaction Sodium + hydrochloric acid sulphur dioxide and sodium chloride Thiosulfate acid + water Na2SO3 (aq) 2HCl (aq) S (s) + SO2 (g) + 2NaCl (aq) + H2O(l) Reactants: Sodium thiosulfate, hydrochloric acid Products: sulphur dioxide and sodium chloride Thiosulfate acid + water This is a irreversible reaction States of matter Name of atom | Chemical symbol | Number used in the chemical reaction | Sodium | Na | 2 | Sulphur | S | 2 | Oxygen | O | 2 |...
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...Experiment 10. The effect of pepsin on egg white suspension (a) Label four test-tubes 1-4. (b) Into each tube place about 5 cm3 (20 mm in test-tube) egg white suspension. (c) To tubes 2,3 and 4 add three drops of dilute hydrochloric acid. (d) Using a graduated pipette or syringe place 1 cm3 1% pepsin solution in a clean test- tube and heat it over a small Bunsen flame until the liquid boils. Add the boiled pepsin to the egg-white suspension in tube 4. (e) Prepare a water bath in a 250 cm3 beaker or jar by mixing hot and cold water from the tap to attain a temperature of about 40 °C. Have the beaker about half full. (f) Using a graduated pipette or syringe, add 1 cm3 1% pepsin to tubes 1 and 3 only. (g) Place all four tubes in the water bath and copy the table below into your notebook. (h) After five or six minutes remove the four tubes from the water bath and replace them in the test-tube rack. Compare the appearance of the contents and fill in your table of results. |Tube |Contents |Results | |1 |Egg-white suspension & pepsin | | |2 |Egg-white suspension & HCl | | |3 |Egg-white suspension, pepsin & HCl ...
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...GCSE DOUBLE AWARD SCIENCE INVESTIGATION Title: Investigating how concentration changes the rate of a chemical reaction | Name: Ryan Bradley | Class: 12A1 | What is the aim of this experiment? To investigate how concentration hydrochloric acid affects the rate of reaction between sodium thiosulphate and hydrochloric acid and water. P.6a: List all the factors that could have an effect on the results in this investigation? * Concentration * Temperature * Surface area * Catalyst * Colour of the X * Stirring the mixture * Water in the beaker from washing out beaker P.6a: P.8a: Explain in detail how each of the factors you named could affect the investigation? Surface Area: This would affect my investigation because if there was a bigger surface area this means the particles have more room to collide as they are more exposed to head on collisions Concentration: If I was to increase the concentrations of the hydrochloric acid by too much/ little this will make my results unreliable because the more hydrochloric acid the more successful collisions and this would increase the rate of reaction. Stirring the mixture: This would affect my investigation because if I was to stir the mixture it would speed up the reaction time as you are creating more collisions meaning the ‘x’ will disappear quicker. Temperature: If I was to increase the temperature this would affect my investigation because it would mean the particles would gain more energy and this would...
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...was made between effectiveness and cost, and to make a final verdict on which tablet can neutralise more acid for equal amounts of money. The ground tablets were placed in an Erlenmeyer flask along with a base, a pH indicator, and water. Hydrochloric acid with a pH of two was slowly released into the mixture using a burette. The observable difference that indicated the desired change in pH was a colour variance of the liquid, created by the indicator. The quantity of hydrochloric acid needed to bring the basicity of the mixture to the right pH was noted, and the procedure was repeated with the other antacid. The results showed that the Tums brand could neutralise more acid, however the Equate brand has a lesser cost per gram. A calculation revealed that the Equate brand was the better choice, since overall it could eliminate more hydrochloric acid than the Tums brand per dollar. Key Terms: Chemical reaction: A reaction in which the ionic or molecular structure of a substance is changed to fulfill the substance’s need of a full valence shell of electrons. pH: Scale used to express how acidic or basic a solution is. The scale ranges from 0-14, with 7 being neutral. Any pH lower than 7 is acidic, and any pH higher than 7 is basic. Antacid: A medicine that neutralises the acidity of your stomach. Titration: As being most commonly associated with reactions between acids and bases, a titration is a process by which a solution is being added to another solution (the addition...
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...with acids (neutralisation titration) will eliminate the third. The analysis of such mixtures can be realised at any technique: 1) direct titration (Warder’s method) or 2) back-titration (Winkler’s method). The analysis of such mixtures requires two titrations: one with an alkaline-range indicator, such as phenolphthalein, and the other with an acid-range indicator, such as methylorange. 1. Direct titration the mixture of Sodium Hydroxide and Sodium Carbonate The composition of the solution can be deduced from the relative volumes of acid needed to titrate equal volumes of the sample. Titration with hydrochloric acid to a phenolphthalein end point (Vphth): NaOH + HCl = NaCl + H2O Na2CO3 + HCl = NaHCO3 + NaCl Titration with hydrochloric acid to a methyl orange end point (Vmo): NaHCO3 + HCl = NaCl + H2O + CO2 Components in sample Relationship between Vphth and Vmo in the titration of an equal volume of sample NaOH Vphth = Vmo Na2CO3 Vphth = 1/2Vmo NaOH + Na2CO3 Vphth > 1/2Vmo 1. Load a burette with 0,1 N hydrochloric acid solution. 2. To conical flask pour in 10 ml aliquot of sample (VS). 3. Introduce 2-3 drops of phenolphthalein solution, and titrate with 0.1 N hydrochloric acid solution until the solution lost the red colour. Read the burette mark (Vphth). 4. To conical flask pour in 10 ml aliquot of sample (VS). 5. Introduce 2-3 drops of methyl orange solution, and titrate with 0,1 N hydrochloric acid...
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...Student name-----Minghao Li Teacher name-----Mr. Kalanderopoulos, J Course code-----SCH4U Abstract The purpose of this lab is to find out the molar enthalpy change of neutralization by mixture sodium hydroxide and hydrochloric acid. To get the result use some related materials and thermometer to measure the temperature of each solution. The formula to describe this mixture reaction is HCl + NaOH → NaCl + H2O (Sodium hydroxide combined with Hydrochloric acid) Purpose To determine the molar enthalpy change of neutralization, for the reaction of aqueous sodium hydroxide and aqueous hydrochloric acid. Hypothesis If Hess’ law is used to calculate the molar enthalpy of combined for HCl and NaOH using experimentally determined enthalpy values, then the final result will be more specific. This is because Hess’ law states that the sum of the enthalpy pages of the intermediate reactions, should equal the enthalpy change of the target reaction. Materials Coffee-cup calorimeter | Strning rod | Two 100 ml graduate cylinders | 1.0 mol/L Sodium hydroxide NaOH (aq) | thermometer | 1.0 mol/L Hydrochloric Acid HCl (aq) | Procedure Safety---before doing the lab, make sure already read the lab safety guidelines. (MSDS of sodium hydroxide and hydrochloric acid). All things that were unrelated and corrosive to the experiment should be clear off the benches. Goggles and glove should be kept on all the time. To start this lab need assemble two coffee-cup calorimeter, each...
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...sand the “glacier” moved around. Chemical Weathering was found to quickly dissolve the marble but not the granite. Oxidation was found to dissolve the pyrite very quickly and continue to dissolve it over the next 2-3 days. Organic Processes were found to have a major physical effect on the paste as it broke it apart. Materials Bean Seeds, 10 Magnifying glass Calcium sulfate, CaSO4, 2 spoonfuls Marker Granite chips, 20 g Paper towels Halite chips, 15 g Pipets, Beral, graduated Hydrochloric acid solution, HCl, 1 M, 15 mL Plastic cups, small, 3 Ice cube Sample container Local rock samples, 2 Sheet of white paper, 8 ½” x 11”, unlined Marble chips, 25 g Spoon Pyrite pieces, 2 Styrofoam tray Sand, 6 spoonfuls Stopwatch...
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...These factors include the following: (1) Temperature: higher the temp-higher the rate of diffusion, (2) Size of particle: bigger the particle-higher the energy to diffuse , (3) State of matter: solid takes more time to diffuse compared to liquids, liquids take more time to diffuse compared to gases and gases take less time to diffuse compared to liquids and solids, (4) Nature of matter: denser the matter-slower the rate of diffusion. My objective was to determine the properties of ammonia (NH3) and of hydrochloric acid (HCl) that are related to diffusion. I hypothesized that ammonia diffuse faster than hydrochloric acid. For more support we conduct also an experiment that would detect the diffusing substances in an agar plate using colored compounds; potassium permanganate, methylene blue and potassium dichromate MATERIALS AND METHODS Materials: 6 test tube (5ml) Chemicals: 1 test tube brush ammonium hydroxide 1 test tube rack hydrochloric acid 1...
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...Experiment 8. The hydrolysis of starch with hydrochloric acid (a) Prepare a water bath by half filling a 250 cm3 beaker with warm water and heating it to boiling point on a tripod and gauze, with a Bunsen burner. When the water boils, reduce the flame to keep the water at boiling point. (b) Label four test-tubes 1-4. (c) Copy the table given below into your notebook. (d) In each tube place 5 cm3 3% starch solution. (e) Using a syringe or graduated pipette, add 3 cm3 Benedict's solution to the starch solution in tube 1 and place the tube in the boiling water bath for five minutes. (f) Rinse the syringe or pipette and use it to add 1 cm3 dilute hydrochloric acid to the starch solution in each of tubes 2, 3 and 4. Note the time and place all three tubes in the water bath. (They will be removed at five, ten and fifteen minutes respectively). (g) Remember to remove tube 1 from the water bath after five minutes if you have not already done so. (h) After five minutes, remove tube 2 from the water bath and cool it under the tap. Neutralize the acid by adding solid sodium bicarbonate, a little at a time, until the addition of one portion produces no fizzing. Place tube in the rack and return to tube 3. (i) After ten minutes in the water bath, remove tube 3, cool and neutralize the contents as described in (h). Place the tube in the rack. (j) After fifteen minutes in the water bath, remove tube 4; cool and neutralize as before, and place it in the rack...
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