General chemistry chemistry


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General chemistry chemistry

  1. 1. 0ÎÖ Chemistry Experiment’s
  2. 2. 1 PrefacePraise we prayed to the divine presence Allah SWT who has given his blessing and gift tous all.Thank Allah SWT, the Chemistry Experiment’s book for chemistry program has to beresolved. This Chemistry Experiment’s book is a reference for students of chemistryprogram of Department of Natural Science Education in Faculty of Tarbiya’ and TeachingScience in performing chemistry experiments related to general chemistry lecture material.My gratitude goes to all those who have helped guide the completion of the ChemistryExperiment’s book, especially for those majoring in Department of Natural ScienceEducation - Faculty of Tarbiya’ and Teaching Science – Syarif Hidayatullah Islamic StateUniversity.Hopefully this book can be useful for all of us. Amiinn.Author ÎÖ Chemistry Experiment’s
  3. 3. 2 ContentPreface .............................................................................................................................. 1Contents ........................................................................................................................... 2Laboratory Rules ............................................................................................................... 3Safety and Health in Laboratory ....................................................................................... 5Experiment I ...................................................................................................................... xxObservation Data Sheet .................................................................................................... xxExperiment II ..................................................................................................................... xxObservation Data Sheet .................................................................................................... xxExperiment III .................................................................................................................... xxObservation Data Sheet .................................................................................................... xxExperiment IV .................................................................................................................... xxObservation Data Sheet .................................................................................................... xxExperiment V ..................................................................................................................... xxObservation Data Sheet .................................................................................................... xxExperiment VI .................................................................................................................... xxObservation Data Sheet .................................................................................................... xxExperiment VII ................................................................................................................... xxObservation Data Sheet .................................................................................................... xx ÎÖ Chemistry Experiment’s
  4. 4. 3 1. Before entering the laboratory, students must use a laboratory coat 2. Each group is required to bring equipments consisting of : • One sheet of hand wipes • One sheet of rag mop • fire lighters • Hands soap • Pipet drops • Tissue 3. In experiments, students must be accompanied by lecturers and or laboratory officer and or assistant 4. Before doing the experiments, students borrow the tools from laboratory officer and fill and signed administration book 5. Students are responsibility to all equipment that borrowed, and should be checked first before the experiments begins. If there is a damaged appliance be reported immediately to the laboratory officer 6. During the experiments progresses, the workplace of each group must be kept clean 7. Cautions !! not allowed to smoke and eat 8. During the experiments, students expected ,always, to be careful and prudent in the use of chemicalsÎÖ Chemistry Experiment’s
  5. 5. 4 9. After the experiments is completed, the workplace of each group must be clean and dry 10. After the experiments, the tools should be returned to the laboratory officer in a clean and dry, and fill out and sign the administration book 11. After the experiments, each group must show the results of experiments to assistant and legalized it, one for archive12. Equipment that is broken intentionally or unintentionally caused by student should be recorded in administration book and should be replaced in accordance with the specification tool, not later than two weeks13. Each student must submit an experiments report not later than one week after the experiment conducted14. Dispose of trash in the trash bagÎÖ Chemistry Experiment’s
  6. 6. 5 The laboratory is a workplace to conduct scientific research. The laboratory is alsoused as a means of experiments for students in a supportive learning done in class.Chemistry laboratory as a means of chemistry laboratory course can not be separated fromthe chemicals and laboratory activities that require the attention of safety. In carrying out students activities in the chemistry laboratory, must be consideredregarding safety. Chemistry laboratories should be sought is a safe place to work and freefrom fears of accidents. The students and laboratory officer jointly responsible foradministering occupational health and safety in the laboratory, in order to do experimentseffectively and efficiently. Here are a few types and signs of the materials or chemicals that need to beconsidered : Classification Symbol Toxic chemicals are chemicals that can cause harm to humans or cause death if inhaled into the body by being swallowed, passing through the respiratory or skin contacts. Examples: benzene, cyanide, chromium, lead, asbestos dust Corrosive chemicals are chemicals that cause damage to living tissue. Examples: sulfuric acid, phenol, formaldehyde ÎÖ Chemistry Experiment’s
  7. 7. 6 Flammable chemicals are chemicals that easily react with oxygen and cause a fire. Example: acetone, phosphorous, benzene, hexene, di ethyl ether The chemical explosive is a solid or liquid substance or mixture of both that due to chemical reaction to produce gas and pressure of spontaneously giving rise to damage. Example: trinitrotoluen, nitroglycerine, ammonium nitrate Oxidizing chemicals are chemicals that can produce oxygen so that other materials may cause fire. Example: potassium chlorate, potassium permanganate, hydrogen peroxide Irritation chemicals are chemicals that can cause inflammation / irritation of the skin, eyes, and breathing. Example: zinc sulfate, potassium permanganate, silver nitrate Chemicals that can pollute / damage the environment if the waste directly into the environment without any processingÎÖ Chemistry Experiment’s
  8. 8. 7Chemical Safety Guidelines Data The term for data safety guidelines for chemicals that are used internationally is theMaterial Safety Data Sheets (MSDS). In the MSDS guidelines, there are four signs thatmust be considered. Blue columns indicate the level of a chemical hazard to health. Redcolumns indicate the level of a chemical hazard to the fire. Yellow column showed levelchemical reactivity. White Columns is a special sign for some chemicals. Figure 1. Symbol of substances / chemicals on the MSDS dataFirst aid in the laboratory Accidents in the laboratory are not expected to occur even if the pattern has beenapplied to K3. Therefore, in doing laboratory work, students and officers need to haveknowledge about the steps to be taken in case of accidents. First aid (P3K) is knowledgethat must be possessed by every students as the prevention of accidents are more severeimpact before getting intensive treatment from the doctor.Here are some kinds of accidents in the laboratory and handling.1. Burn If the body burns due to heat, basting with livertran ointments, butter or pikrat 3% acid solution. If the wound is large enough flush with 1% bicarbonate solution and immediately take it to the nearest clinic. ÎÖ Chemistry Experiment’s
  9. 9. 82. Skin exposed to concentrated acid If the skin is exposed to splashing Sulfuric acid, or Nitric acid, immediately wiped with tissue paper and then wash with water and Sodium bicarbonate. Drain and spread with ointment livertran.3. Skin exposed to strong base Immediately wash with tap water that much, then with 1% Acetic acid solution and rinse again with water. After dry rubbing with ointment livertran.4. Skin exposed to bromine water Immediately wash with Benzene and basting with the Glycerine. After a while washing the rest of glycerin with water and spread with ointment livertran.5. Skin exposed to organic substances If the skin is exposed to the corrosive organic substance, wash it with Alcohol, then wash again using soap and warm water.6. Eyes affected by acid / base a. If dilute acid, wash the eye with a solution of Sodium bicarbonate 1% using eye wash equipment. b. If a concentrated acid, first wash with water as much as possible, then wash with a solution of Sodium bicarbonate 1%. c. If the eyes exposed to alkali, washing with water and 1% Boric acid solution.7. Solids, liquids, and toxic gases a. If the toxic substances into the mouth but not swallowed. Substance is released immediately and rinse with water as much as possible. b. If the acid solution ingested, immediately drink water as much as possible. Then drink water slurry of lime or magnesia and pure milk. If a strong base which is swallowed, immediately drink as much as possible, then drank a solution of diluted vinegar, lemon juice, lactic acid, after that drink whole milk. c. Arsenic or Mercury compounds are swallowed, promptly drink salt solution made by dissolving one teaspoon of salt in a glass of warm water. ÎÖ Chemistry Experiment’s
  10. 10. 9 d. If inhaled chlorine gas or bromine, open upper garment immediately inhale ammonia or gargle with a solution of bicarbonate. Furthermore, menthol smoke or drink hot liquids like peppermint.Terms - conditions of storage material In applying the pattern of K3 in the laboratory, need to be considered also onstorage of chemicals. This is intended to avoid the occurrence of fire, explosion, or leakageof chemicals. Effect of heat / flame, the effect of moisture, interaction with the container,the interaction with light, and the interactions between chemicals should be considered instorage. As already noted earlier on the types and signs of chemical, then some way ofstoring chemicals described as follows. 1. Flammable chemicals stored at low temperature and ventilated, kept away from sources of ignition. Example: ether, alcohol, acetone. 2. Corrosive chemicals are stored in low-temperature room, a sealed container and separated from toxic substances. Example: alkali metals, acid anhydride. 3. Toxic chemicals are stored in low-temperature room, away from the danger of fire, separated from other materials that might react. Examples: cyanide, phosphorus, arsenic. 4. Irritant chemicals stored in confined spaces, low temperature, and in isolation from student. Examples: silver nitrate, Sodium hydroxide, barium chloride. 5. Oxidizing chemicals are stored in low temperature space, ventilated, kept away from sources of ignition, material or kept away from flammable liquids. Example: perchlorate, permanganate, peroxide. 6. Pressurized gas stored in a state of standing upright and vertical, kept away from the fire, kept away from corrosive materials. Example: nitrogen gas, acetylene, hydrogen, etc..Laboratory Techniques Implementation of an effective working atmosphere and efficient can be realized byobserving the pattern of occupational safety and health (K3) in doing the work in the ÎÖ Chemistry Experiment’s
  11. 11. 10laboratory. Laboratory techniques and skills is needed in order to realize this. Thefollowing will be shown some basic skills of science laboratory technique.1. Measuring the volume of solution: Volumetric glassware is used for precise and accurate volumes. The types of volumetric glassware you will use are volumetric flasks, volumetric pipets and burets. Flasks and pipets are in your locker while Figure 2. Meniscus of solution burets are located at your workbench or in one of the fume hoods. To read the liquid level in all of these, find the bottom of the meniscus and readaccurately from the graduations on the vessel. With volumetric flasks/pipets, align thebottom of the meniscus with the etched mark. When you do this, make certain that youreye is at the same level of the meniscus to avoid error due to parallax. Be sure to weargloves when rinsing the volumetric pipet with the solution. Volumetric pipets, like our 10 mL one, are used to transfer liquids or aqueoussolutions. Always use a rubber bulb to fill pipets. It has a fixed silicone rubber adapter thatcan take pipets of different sizes. If you accidentally let a liquid or solution get into thebulb, empty the bulb at once and try to dry it with Kim wipes. The first step is to rinse the pipet with deionized water. Pour deionized water into abeaker. Squeeze the end of the bulb with one hand and gently place the pipet inside it.Apply a gentle downward pressure on the bulb to make an airtight seal, and squeeze outsome of the air in the bulb. Place the tip of the pipet into the beaker and ease up on thesqueezing to draw water into the pipet until its approximately half full. Have your indexfinger or thumb ready to quickly place it on the opening of the pipet as soon as you removethe bulb from the pipet. This prevents the water from running out. Turn the pipet horizontaland gently roll it so the water wets the entire inside surface. Once youre finished rinsing,drain the pipet in the sink. Before you can use the pipet to transfer your solution, you should rinse it with thesolution. Pour the solution into a beaker. Attach the pipet to the bulb as you did in step 1.Place the tip of the pipet into the beaker and draw solution into the pipet by releasing ÎÖ Chemistry Experiment’s
  12. 12. 11pressure on the bulb. Once its filled halfway, remove the bulb and quickly place yourindex finger on top. Turn the pipet horizontal and gently roll it to wet the inside surface.Discard the rinse solution into an appropriate waste container. After one rinsing (or two ifdesired), the pipet is ready for use. Make sure you have enough solution in your beaker and have the beaker to whichyou will transfer the solution handy. As you did in steps 1 and 2, attach the pipet to thebulb to draw the solution into the pipet. Avoid drawing the solution into the bulb. This timeyou need to draw enough solution so that the meniscus is above the etched mark. Removethe bulb and quickly place your index finger on top of the pipet. Note that if you dont draw enough solution into the pipet, you may have to squeezethe bulb again at least once to draw in enough solution. Remember to use your finger tohold the solution in. Remove the pipet from the solution, and wipe the pipets tapered end with a Kimwipe. Then, holding the pipet in one hand and the waste container in the other, let thetapered end of the pipet touch the edge of the beaker. Bring the meniscus to your eye leveland release your finger slightly from the top of the pipet so the meniscus drops slowly tothe etched mark. When you think the bottom of the meniscus reaches the etched mark,reassert pressure on the top of the pipet. There should be exactly 10 mL of solution in thepipet. With the pipet in one hand and the beaker into which you want to transfer thesolution in the other, place the tip of the pipet on the edge of the beaker. Remove yourindex finger from the top of the pipet so the solution flows into the beaker. After draining the solution into the beaker, you will notice a small amount of liquidin the end of the pipet. Since this pipet is marked TD, meaning To deliver, the smallamount of liquid remaining at the tip should not be blown out. ÎÖ Chemistry Experiment’s
  13. 13. 122. How to Fold Filter Paper Filter paper is paper specially designed with "pores" so it can be used to separate acomponent from a mixture. Filters used in everyday life, such as in coffeemakers orfurnaces, are easy to use. In a laboratory, however, the basic piece of filter paper iscircular-shaped, and it must be folded before it can be used in a funnel. a. The basic filter paper used in the laboratory is a flat, circular-shaped paper that feels something like construction paper. If it is a new piece of filter paper, it will be perfectly flat with no folds or creases. b. Fold your piece of filter paper in half. It will have the shape of half of a pizza. c. Fold your piece of filter paper in half again. It now has the shape of one-fourth of a pizza. d. Your filter paper is now folded into four layers. To use the filter paper, open it up into a cone shape, with three layers on one side of the cone and one layer on the other. It will have a cone shape. e. Your folded filter paper is now ready to use. You should wet the filter paper before you place it into the funnel. The seal that is created between the funnel and the wet filter paper will actually quicken the filtering process. Set it inside a funnel to give it support. ÎÖ Chemistry Experiment’s
  14. 14. 13 Do not poke holes in your filter paper. Filter paper has pores already, and even though you may not be able to see them, they are designed to pass substances that are small enough. This is why you can buy different types of filter paper, depending on the size of the substance you want to pass through.3. Smelling chemicals or solutions To recognize the smell of a substance that evaporates easily done by placing thecontainer substance / tube ± 25 cm from the nose. Shake off steam at the top of thecontainer by hand so that they can smell the smell. Figure 3. Smelling chemicals or solutions4. Heating Substances Eye protection should be worn whenever a substance is heated !!. Heating substances is always exciting but it is essential to keep the amounts usedto a minimum and to use the correct apparatus in the recommended manner. Although improvised containers can be used, the notes here refer only to the piecesof laboratory apparatus most commonly used for heating substances:ignition tubes (small test-tubes); test-tubes; boiling tubes (large test-tubes); beakers; evaporating basins; crucibles. ÎÖ Chemistry Experiment’s
  15. 15. 14Heating solids in test–tubes Wear eye protection. Only fill to a maximum of 1/5 full. Use a suitable test-tube holder. Hold the test-tube at a slight angle (see diagram). Ensure that the open end of the test-tube isn’t pointing directly at anybody. Hold the test-tube so that the bottom is just in the tip of the flame. Always start heating with a small, gentle flame.Heating liquids in test tubes Wear eye protection. Use a boiling tube (wide diameter) anddo not fill to more than 1/10 full. Add an anti-bumping granule togive smoother boiling. Add the granule before starting to heat. Use asuitable holder. Hold the tube at an angle so that the top is well awayfrom the flame. Hold the test-tube so that the bottom is just in the tip of theflame. Keep the liquid in the tube moving gently. For flammable liquids, use a water bath.Heating flammable liquids Wear eye protection. Use a boiling tube (wide diameter) and do not fill to more than 1/10 full. Add an anti-bumping granule to give smoother boiling. Add the granule before starting to heat. DO NOT heat directly over a naked flame. Stand the tube in a beaker of hot water (e.g. from a kettle or hot tap).Heating in beakers (and conical flasks) Beakers should only be filled to 1/3 of their capacity when used for heating liquids.The addition of a few ‘anti-bumping’ granules will ensure smoother boiling.Heating in evaporating basins A flat-bottomed evaporating basin can be heated by supporting it on a wire gauzeon a tripod. A round-bottomed evaporating basin is very unstable on a wire gauze soshould be supported on a pipe-clay triangle when heating. ÎÖ Chemistry Experiment’s
  16. 16. 15Evaporating basins should be filled to between 1/3 and 1/2 full. When evaporating salt solutions, the solution should be heated (with occasionalstirring using a glass rod), until solid just appears evenly around the edge of the liquid. Thesolution can then be left to cool - possibly overnight (labelled with names of the owners,the chemicals and any relevant safety warnings).Heating in crucibles A crucible must be heated on a pipe-clay triangle and not on a gauze. Start with asmall, gentle flame before gradually increasing the heating rate. Allow plenty of time in thelesson for crucible and contents to cool down.5. Pouring chemicals a) Pouring liquids Always read the label on a reagent bottle before using its contents. Always wear safety goggles when using an open flame or handling chemicals. Never touch chemicals with your hands. Never return unused chemicals to their original containers. To avoid waste, do not take excessive amounts of reagents. Follow these procedures, demonstrated by your teacher when pouring liquids: Use the back of your fingers to remove the stopper from a reagent bottle. Hold the stopper between your fingers until the transfer of liquid is complete. Do not place the stopper on your workbench. Grasp the container from which you are pouring with the palm of your hand covering the label. When you are transferring a liquid to a test tube or measuring cylinder, the container should be held at eye level. Pour the liquid slowly, until the correct volume has been transferred. When you are pouring a liquid from a reagent bottle into a beaker the reagent should be poured slowly down a glass stirring rod. When you are transferring a liquid from one beaker to another, you can hold the stirring rod and beaker in one hand. ÎÖ Chemistry Experiment’s
  17. 17. 16 Figure 4. Pouring the solution from reagent bottle b) Pouring solids In pouring chemicals in the form of solids, provide a piece of paper ± 15 cm wide and 2 cm, then insert into a test tube with leaves ± 1.5 cm above the mouth of the tube. Pour solids on the paper. Next, hold the paper and straighten the upper end of vertical tube, and lift the paper. Figure 5. Pouring solids to the test tube6. Dilution of concentrated acid In conducting dilution of concentrated acid or liquid chemicals that areexothermic, heat generated note. First, prepare a beaker or other container which alreadycontains the distilled water that has been calculated according to the volume dilution of ÎÖ Chemistry Experiment’s
  18. 18. 17concentration desired. Then take the concentrated acid using volumetric pipet with bulbpipet in accordance with the volume of the desired concentration. After that, slowly pourthrough the walls of the beaker until the concentrated acid at low volumetric pipet.CAUTION !! use rubber gloves, goggles, and masks. Do as possible in the acid room.7. Balance When a balance is required for determining mass, you will use a centigrambalance. See figure below. The centigram balance is sensitive to 0.01 g. This means thatyour mass readings should all be recorded to the nearest 0.01 g. Before using the balance, always check to see if the pointer is resting at zero. If thepointer is not at zero, check the slider weights. If all the slider weights are at zero, turn thezero adjust knob until the pointer rests at zero. The zero adjust knob is usually located atthe far left end of the balance beam. See Figure 1-5. Note: The balance will not adjust tozero if the movable pan has been removed. Whenever weighing chemicals, always useweighing paper or a glass container. Figure 6. Centigram balance ( O Hauss balance)Never place chemicals or hot objects directly on the balance pan. They canpermanently damage the surface of the balance pan and affect the mass weighing. In many experiments you will be asked to weigh out a specified amount of achemical solid. ÎÖ Chemistry Experiment’s
  19. 19. 18 CAUTION Do not touch chemicals with your hands. Always wear gloves, apron, and safety goggles when handling chemicals. Carefully check the label on the reagent bottle or container before removing any of the contents. Never use more of a chemical than directed; you should know the locations of the safety shower and eyewash and how to use them in case of an accident. Figure 7. Completness in the laboratoryÎÖ Chemistry Experiment’s
  20. 20. 19Purpose Make a solution of NaCl / Harnstoff 0.2 M of 250 mlOverview In chemistry, a solution is a homogeneous mixture composed of only one phase. Insuch a mixture, a solute is dissolved in another substance, known as a solvent. Thesolvent does the dissolving. Homogenous means that the components of the mixtureform a single phase. The properties of the mixture (concentration, temperature, density,etc.) can be uniformly distributed through the volume but only in absence of diffusionphenomena of after their completion. Usually, the substance present in the greatestamount is considered the solvent. Solvents can be gases, liquids, or solids. One or morecomponents present in the solution other than the solvent are called solutes. The solutionhas the same physical state as the solvent. It is common practice in laboratories to make a solution directly from its constituentingredients. This requires determining the right amount of solvent/solute for specificconcentration. There are three cases in practical calculation: Case 1: amount of solvent volume is given. Case 2: amount of solute mass is given. Case 3: amount of final solution volume is given.In the following equations, A is solvent, B is solute, and C is concentration. Solute volumecontribution is considered through ideal solution model. ÎÖ Chemistry Experiment’s
  21. 21. 20 Case 1: amount (ml) of solvent volume VA is given. Solute mass mB = C VA dA /(100- C/dB) Case 2: amount of solute mass mB is given. Solvent volume VA = mB (100/C-1/ dB ) Case 3: amount (ml) of final solution volume Vt is given. Solute mass mB = C Vt /100; Solvent volume VA=(100/C-1/ dB) mB Case 2: solute mass is known, VA = mB 100/C Case 3: total solution volume is know, same equation as case 1. V A=Vt; mB = C VA /100Materials and apparatus Apparatus Materials O Hauss balance 10 ml Volumetric pipet Table salt Spatula 100 ml beaker glass Harnstoff Watch glass Tripod and asbestos gauze Aquadest 200 mL beaker glass Alcohol burner Stirer bar Wash bottle Glass funnel Filter paper 250 ml Volumetric flask Mortar and pestle Stative and ringProcedures : 1. For the 250 ml 0,2 M Sodium Chloride solution, calculate the mass of Sodium Chloride. Mass of Sodium Chloride is .............. grams. 2. Fill 250 ml beaker glass with Sodium Chloride wich has been weighed. Add 150- 200 ml aquadest, than stirer until all salt dissolve. Afterward, filter the solution using filter paper. 3. Pour the salt into volumetric flask, then add aquadest to mark boundaries. Shake until homogeneous. 4. Take 200 ml of solution in the flask, and enter into a 200 ml beaker. Then take 50 ml of solution using a volumetric pipet, then enter into a 100 ml beaker. ÎÖ Chemistry Experiment’s
  22. 22. 21 5. Heat the solution using a medium heat until crystals formed. Weigh the crystals formed. Mass of crystal is ........... grams. 6. Take few of crystal and observed under microscope. Sketches of crystal formed.Pre lab questions 1) What is the function of volumetric flask in these experiments? Why using volumetric flask not another measure tools? 2) in making 100 ml CaCO3 2M solution, how many grams CaCO3 that must be weighed? 3) What is crystal and crystallization?Post lab questions 1) Mentioned usefulness of saltpeter in daily life. 2) Write the procedure for making 250 ml CuSO4 1M solution. 3) Calculate the KIO3 in table salt. 4) What shape of crystal that yield from experiment. ÎÖ Chemistry Experiment’s
  23. 23. 22 OBSERVATION DATA SHEET Title : Date : Purpose : Sketch of Procedure ObservationsÎÖ Chemistry Experiment’s
  24. 24. 23 Initial mass of Sodium Chloride : Crystal mass of Sodium Chloride : Shape of Sodium chloride crystal : Sketches of crystal shape :Calculation :Analysis of data : ÎÖ Chemistry Experiment’s
  25. 25. 24Conclusion : TangSel, .............................., 20..... Assistant .................................................. ÎÖ Chemistry Experiment’s
  26. 26. 25Purpose : Perform the process of separation and refining of liquids by distillation and extraction. Perform the process of purification of solids by sublimation. Perform separating of liquids by paper chromatographyOverview : The process of separation and purification of a substance from other substancesthat are not desirable, is a very important process in the manufacture of a compound.There are various ways of separation and purification of a substance from the physicallmixtures, among others: liquid-liquid separation can be done by distillation, extraction, and coagulation solid-liquid separation can be done by decantation, filtration, adsorption, anddistillationSome of the separation process to be performed on this experiment, among others:1. Distillation Distillation is the process of separation and purification of substances based ondifferences in boiling point of each substance. Vapor pressure is one physical trait that ÎÖ Chemistry Experiment’s
  27. 27. 26each liquid. At the boiling liquid, vapor pressure equal to the outside air pressure. At thistemperature all the molecules of liquid have enough energy to turn into the gas phase. Indistillation, the gas formed is cooled through a condenser and then accommodated. Theexistence of differences in boiling points of substances in a mixture, each substance willbe collected at different temperatures, allowing the separation and purification of certainsubstances. Better separation would occur if each agent has a boiling point difference isquite large. Various kinds of distillation processes include distillation terraced, vacuumdistillation, etc..2. Extraction Extraction is the process of taking substances from mixtures based on differences insolubility of the substance between two solvents are not mutually interfere. In thisprocess, a solvent is added to the mixture so that the desired substance is soluble, butother substances in the mixture should not come late, so that these substances can beseparated from the mixture. In the extraction process used separating funnel and shaking.3. Sublimation Sublimation is the process of purification of solids by heating so that the substancemay change phase directly from solid phase into the gas phase and back again to the solidphase in the prepared container. This process is very effective for purifying certain solidsbecause of its ability to change phase from solid to gas is not owned by the impurity-substances, so that the products being stored can be ascertained from this process ispure. ÎÖ Chemistry Experiment’s
  28. 28. 274. Paper chromatography Chromatography is a method used to separate molecular mixtures based on thedistribution of molecules in the mixture with the stationary phase (adsorbent) and mobilephase (eluent). Distribution of the phase distribution of molecules can be eitheradsorption or partition the phase distributions.Materials and apparatusApparatus : Distillation set, Separating funnel, 250 ml Erlenmeyer flask, Beaker glass,Stirer bar, Pipet droper, Mortar and pestle, Glass funnel, Filter paper, Stative, clamp danring, Watch glass, Tripod and asbestos gauze, Measurement cylinder, wash bottle.Materials : Iodine, n-hexane, Naphtalene, Ice cube, Chloroform, Aquadest, Methanol,Marker.Procedure :Distillation1. Arrange a tool such as a picture set of tools distillation. Note the flow of water in the condenser!.2. Take 100 ml of sample solution, then pour into the distillation flask using a funnel.3. Enter a boiling stone, and then heat the flask.4. Record the temperature when destilat began to trickle and watch the trend of rising temperatures.5. Stop heating when the liquid in the flask is low so destilat uncontaminated and easily cleaned pumpkin.Extraction 1. Weighing 0.005 g I2 and then insert it into the erlenmeyer flask. 2. Adding 30 ml of water, stir the solution, and enter into a separating funnel. 3. Add 30 ml chlorofrom (CHCl3), and shake thoroughly for 5 minutes with occasional uncorked. ÎÖ Chemistry Experiment’s
  29. 29. 28 4. Squelch a few minutes so as to form two layers. 5. Separates the bottom layer with top layer and stored in two different containers. 6. Adding back Chlorofrom in water solution remaining in the separating funnel, shake for several minutes, then set aside some time. 7. Separating the back between the bottom layer with top layer. 8. Calculate the concentration of iodine in the extraction of 1x and 2x extraction.Sublimation 1. Enter the gross that has been refined Naphthalene in 100 ml beaker. 2. Close the beaker with a watch glass. 3. Put ice on a watch glass. 4. Heat the beaker gently using a hotplate or burner methylated. Naphthalene will vaporate and then crystallized at the bottom of the watch glass. 5. When finished collect the crystals formed. Note the difference in appearance before and after the Naphthalene sublimation.Chromatography 1. Cut filter paper to the size of p = 9cm; l = 2cm. make a point of using colored markers. 2. Enter a ± 5 ml of solvent into the container. 3. Insert the filter paper into the container to touch the paper base solution. Then hang over the mouth of the container. 4. Observe the changes that occur, then calculate its Rf.Analisis data Analyze the data obtained, such as when the temperature begins to drip and colordestilat; physical shape of each layer in the extraction phase; physical form crystals beforeand after sublimation; count on a chromatographic Rf. Compare data with references thatyou know and point out your argument about that fact. ÎÖ Chemistry Experiment’s
  30. 30. 29Series of toolsQuestionsPre-lab questions1. What is the boiling point?2. Is the function of the boiling rock?3. Name the distillation process applications in the life or industrial? explain!4. What are the criteria used for the extraction solvent?5. What are polar and non polar solvents?6. Mention of other solid substances which undergo a process of sublimation (3)? ÎÖ Chemistry Experiment’s
  31. 31. 30Post-lab questions1. Is a simple distillation can be used to separate liquids with boiling points of adjacent? if not, what alternatives do you suggest?2. Which produces better separation: 20 ml of the mixture is separated using 100 ml of solvent with a one-time, or 20 ml of the mixture were separated using 20 ml of solvent with 5 times the process? why?3. Explain how crystals can form in the watch glass? whether the sublimation process can be applied to all solids?4. Why in the chromatography experiments formed a different color from the color of the origin of the markers? ÎÖ Chemistry Experiment’s
  32. 32. 31 OBSERVATION DATA SHEET Title : Date : Purpose :Distillation Sketches of procedures Observation ÎÖ Chemistry Experiment’s
  33. 33. 32 Volume of sample : color of solution before distillation : color of solution after distillation : Temperature of destilat start trickling :Extraction Sketches of procedures Observation ÎÖ Chemistry Experiment’s
  34. 34. 33Before extraction Color of I2 solution : Color of chloroform :After extraction Color of the upper layer : Color of the bottom layer :Sublimation Sketches of procedures Observation ÎÖ Chemistry Experiment’s
  35. 35. 34Before sublimation Color of the crystal : Shape of crystal :After sublimation Color of crystal : Shape of crystal :Paper chromatography Sketches of procedures Observation ÎÖ Chemistry Experiment’s
  36. 36. 35Marker color :Colors after separation :Analysis of Data : ÎÖ Chemistry Experiment’s
  37. 37. 36Conclusion : TangSel, ............................. 20...... Assistant ......................................... ÎÖ Chemistry Experiment’s
  38. 38. 37Purpose 1. Making standard solution (Oxalic acid) to standardize Sodium hydroxide solution 2. Determining the molar mass of the titrated acid solutionOverview Find out the references about the acid-base titration (i.e. standard solution, typeof standard solution, titration curve, titration end point, etc.) from chemistry for collegetextbook and another references, i.e. handbook, website !. References should be takenfrom two textbook of chemistry for college.Material and apparatus Apparatus : Materials : 250 ml volumetric flask 250 ml erlenmeyer Oxalic acid 0,05M 200 ml beaker glass flask NaOH 0,1 M 100 ml beaker glass Stirer bar White Vinegar 50 ml buret Analytical balance Limo orange Glass funnel wash bottle Aquadest 25 ml volumetric pipet Stative and clamps Phenolfthalein Drop pipet SpatulaProceduresPart I : Preparation of a primary standard acid 1. Before coming to thr laboratory, calculate the mass of Oxalic acid. H2C2O4.2H2O that you will need to make up 250 ml of a 0,0500 M solution. 2. Put on your lab apron and safety googles. 3. Top load the amount of Oxalic acid that you have calculated into a 100 ml beaker ÎÖ Chemistry Experiment’s
  39. 39. 38 and accurately record the mass ot the Oxalic acid in the table. Do not spend too much time trying to get exactly the same mass as you calculated. The important things is to record accurately the mass you do have and to calculate the molarity of Oxalic acid from this mass. For example, the mass you use may give the solution a molarity of 0,0496 M. This is perfectly acceptable, provided that you use this figure in your calculations. 4. Dissolve the Oxalic acid in water, and pour the solution through a funnel into a 250 ml volumetric flask. Wash the beaker with water twice, and add these washngs to the flask. Now add water to the flask until the level is up to the mark. Use a wash bottles you get closer to the mark. Stopper the flask, and shake to ensure the solution is homogeneous. You now have your standard solution of Oxalic acid.Part II : standardization of an unknown NaOH solution 1. Obtain a 100 ml beaker and fill it with NaOH solution of unknown molarity. Label it NaOH. 2. Add about 15 ml of the NaOH solution solution to the buret through a funnel, rinse it back and forth, and then discard it through the tip into the sink. Repeat. 3. Fill up the buret with more NaOH solution and allow some to drain in order to remove any air bubbles in the tip. Remove the funnel. 4. Using the suction bulb on the end of your pipet, withdraw about 5 ml of Oxalic acid, rinse it around pipet, and discard it. Repeat. Withdraw 25 ml of the standard Oxalic acid solution and transfer it to a 250 ml erlenmeyer flask. The correct volume is delivered when you have touched the tip of the pipet to the side of the flask. Do not blow through the pipet. (Note : NEVER pipet from the volumetric flask, you will have to transfer the Oxalic acid first to clean, dry 100 ml beaker and then pipet out of the beaker). 5. Add 3 drops of Phenolphtalein solution to the acid in the erlenmeyer flask. 6. Read the initial volume of NaOH in the buret accurately and record it in the table. ÎÖ Chemistry Experiment’s
  40. 40. 39 Then open the valve on the buret. Allow the NaOH solution to run into the flask and swirl constantly to ensure thorough mixing. 7. After a time, you will notice a pink color that appears where the NaOH solution enters the liquid in the flask. When this color takes a longer time to disperse and disappear, slow down the rate of addition of NaOH until eventually you are adding it a drop at a time. Stop the titration when the faintest possible pink color stays in the flask for about 20 s. Read the final volume of the NaOH in the buret and record it in the table (the difference between the initial reading and the final reading represents the volume of NaOH required to neutralize the Oxalic acid). 8. If you are at all in doubt as to whether you have a pale pink color, take the reading anyway, then add one more drop. If the color immediately becomes darker, the reading you took is probably the most accurate result. This is called the end point of the titration. Discard the solution down the sink. 9. Pipet another 25 ml of Oxalic acid into the flask and again add 3 drops of Phenolph talein. Refill the buret (if necessary) and repeat the titration. Run in NaOH to within 1 ml of the volume needed in the first titration, then add the solution a drop at a time, swirling after each drop, until you get the faint pink endpoint. Repeat the titration until you have two readings that agree to within 0,08 ml.Part III : determination of the molar mass of an unknown solid acid 1. Obtain a vial containing an unknown solid acid from your teacher. Record the identifying number or letter in the table. 2. Weight out about 0,40 g of the solid acid into a clean, dry beaker, and record the mass accurately into table. It does not have to be exactly 0,40 g as long as you know exactly how much you have. 3. Dissolve the acid into approximately 40 ml of water and transfer the solution to an erlenmeyer flask. Rinse the beaker twice to ensure that all the acid solution is transferred (the amount of water added does not alter the results). Add 3 drops of Phenolphtalein. ÎÖ Chemistry Experiment’s
  41. 41. 40 4. Run in NaOH from a buret as in part II, measuring the volume required to reach the endpoint. Record this figure in table. 5. Repeat steps 2 and 4 until you get two readings in close agreement. If you do not have exactly the same mass each time, check whether the results agree by determining the ratio of the volumes and comparing it with the ratio of the masses used.QuestionsPre lab questions The molarity of a hydrochloric acid solution can be determined by titrating a known volume of the solution with a Sodium hydroxide solution of known concentration. If 14.7 mL of 0.102 M NaOH is required to titrate 25.00 mL of a hydrochloric acid, HCl, solution, what is the molarity of the hydrochloric acid?Post lab questions The molarity of a Sodium hydroxide solution can be determined by titrating a known volume of the solution with a Hydrochloric acid solution of known concentration. If 19.1 mL of 0.118 M HCl is required to neutralize 25.00 mL of a Sodium hydroxide solution, what is the molarity of the Sodium hydroxide? ÎÖ Chemistry Experiment’s
  42. 42. 41 OBSERVATION DATA SHEET Title : Date : Purpose :Part I Sketches of procedures Observation Calculated mass of Oxalic acid Required for 250 ml of 0,050M solution (g) Mass of Oxalic acid used (g) ÎÖ Chemistry Experiment’s
  43. 43. 42Part II Sketches of procedures Observation Trial 4 Trial 1 Trial 2 Trial 3 (if necessary) Initial reading of buret (ml) Final reading of buret (ml) Volume of NaOH required (ml) Average volume of NaOH (ml) ÎÖ Chemistry Experiment’s
  44. 44. 43Part IIIUnknown solid acid : .................................... Sketches of procedures Observation Trial 4 Trial 1 Trial 2 Trial 3 (if necessary) Mass of acid (g) Initial reading of buret (ml) Final reading of buret (ml) Volume of NaOH required (ml) Average volume of NaOH (ml) ÎÖ Chemistry Experiment’s
  45. 45. 44Calculations :Analysis of data : ÎÖ Chemistry Experiment’s
  46. 46. 45ÎÖ Chemistry Experiment’s
  47. 47. 46Conclusion : TangSel, ............................. 20...... Assistant ......................................... ÎÖ Chemistry Experiment’s
  48. 48. 47Purposes Observe the chemical changes indicative of chemical reactionsOverview A chemical reaction is a process that leads to the transformation of one set ofchemical substances to another. Chemical reactions can be either spontaneous, requiringno input of energy, or non-spontaneous, typically following the input of some type ofenergy, viz. heat, light or electricity. Classically, chemical reactions encompass changesthat strictly involve the motion of electrons in the forming and breaking of chemicalbonds, although the general concept of a chemical reaction, in particular the notion of achemical equation, is applicable to transformations of elementary particles, as well asnuclear reactions. The substance (or substances) initially involved in a chemical reaction are calledreactants or reagents. Chemical reactions are usually characterized by a chemical change,and they yield one or more products, which usually have properties different from thereactants. Reactions often consist of a sequence of individual sub-steps, the so-calledelementary reactions, and the information on the precise course of action is part of thereaction mechanism. Chemical reactions are described with chemical equations, whichgraphically present the starting materials, end products, and sometimes intermediateproducts and reaction conditions. Different chemical reactions are used in combination inchemical synthesis in order to obtain a desired product. The characteristics of chemical ÎÖ Chemistry Experiment’s
  49. 49. 48reactions are : Evolution of gas, Formation of a precipitate, Change in color, Change intemperature, and Change in state.Material and apparatus Apparatus : Materials : Test tube ZnSO4 0,1 M Oxalic acid 0,1M Spatula NH4OH 1M H2SO4 2 M Test tube proof BaCl2 0,1 M KMnO4 0,05M Rubber tube K2CrO4 0,1 M FeSO4 0,1 M Drop pipet HCl 0,1 M Aluminium foil CaCO3 lumps HCl 3 MProcedures1. Precipitate formation Zinc Deposition a. Add 1 ml of 0.1 M ZnSO4 into a test tube, then add 1 ml of 1 M NH4OH Record your observations!. b. Add back in the tube above the solution with 1 M NH4OH little by little. Record your observations! . The precipitate Barium a. Take 1 ml of 0.1 M BaCl2, enter into a test tube, then add 1 ml of 0.1 M K 2CrO4 observe what happens. b. Add 1 ml of 0.1 M BaCl2 solution into a test tube, then add into 1 mL of 0.1 M HCl and then add another 1 ml of 0.1 M K2CrO4 Observe and record your observations.2. Reaction gas formation a. Take 1 piece of tube and attach the hose pipe on the side of the tube to drain the gas reaction products. b. Put 2 grams of limestone (CaCO3) into the reaction tube at the top, then add 3 mL of 3M HCl, immediately close the tube with a cork / rubber and tebentuk gas flowed into the clear water solution of Ba(OH)2. Notice what happens. ÎÖ Chemistry Experiment’s
  50. 50. 493. The reaction changes the color a. Into a mixture of 1 ml of 0.1 M H2C2O4 and 2 drops of H2SO4, enter drop by drop until the color of KMnO4 solution of KMnO4 is lost. b. To a solution of 0.1 M FeSO4 add 2 drops of 2 M H2SO4, and add dropwise 0.1 M KMnO4 Sprinkle 2 drops of 2 M H2SO4, and add dropwise 0.05 M KMnO4 Compare the speed of color loss of KMnO4 in experiments 3a and 3b.4. Reaction temperature changes Exothermic Enter into a test tube a small piece of aluminum foil. Then add 1 M HCl Observe the changes that occur by holding the tube wall. Endothermic Enter into a test tube and a half tablespoons of harnstoff, then add water. Observe the changes that occur by holding the tube wall.Analysis of data Write down the equation of each experiment performed. Count the number of moles of precipitate formed during the experiment D1. Count the number of moles of gas formed during the experiment D2.Pre-lab questions 1. Mention the characteristics of chemical reactions. 2. What is the difference between endothermic and exothermic reactions? 3. Write the equation of chemical reaction that produces a color change, precipitate formation, temperature changes, and gas formation. (Respectively 2).Post-lab questions 1. In experiment D3, how the ratio of the speed loss in the second reaction of KMnO 4 color? explain! 2. What causes temperature changes in the experiment D4? 3. Mention examples of the four characteristics of chemical reactions in dayli life. ÎÖ Chemistry Experiment’s
  51. 51. 50 OBSERVATION DATA SHEET Title : Date : Purpose :Precipitate formation Sketches of procedures Observation ÎÖ Chemistry Experiment’s
  52. 52. 51 Zinc deposition Chemical reaction Change after reaction ZnSO4 + NH4OH ZnSO4 + NH4OH + NH4OH Precipitation of Barium Chemical reaction Change after reaction BaCl2 + K2CrO4 Chemical reaction Change after reaction BaCl2 + HCl BaCl2 + HCl + K2CrO4Gas forming from reaction Sketches of procedures Observation ÎÖ Chemistry Experiment’s
  53. 53. 52 Chemical reaction Change after reaction CaCO3 + HCl vapor + Ba(OH)2Color change from reaction Sketches of procedures Observation ÎÖ Chemistry Experiment’s
  54. 54. 53 Chemical reaction Change that occurH2C2O4 + H2SO4H2C2O4 + H2SO4 + KMnO4 Reaction Change that occurH2C2O4 +H2SO4 + KMnO4 0.1 MH2C2O4 + H2SO4 + KMnO4 0.05 MTemperatur change from reaction Sketches of procedures ObservationExothermic Reaction Change occurAluminium foil + HCl 1 M ÎÖ Chemistry Experiment’s
  55. 55. 54Endothermic Reaction Change occur ZnSO4 + H2OChemical equations:Analysis of data : ÎÖ Chemistry Experiment’s
  56. 56. 55Conclusion : TangSel, .................................. 20.... Assistant, ............................................ ÎÖ Chemistry Experiment’s
  57. 57. 56Purpose Determine the reaction rate coefficient based on the formation of deposits.Overview Stoichiometry is a branch of chemistry that deals with the relative quantities ofreactants and products in chemical reactions. In a balanced chemical reaction, therelations among quantities of reactants and products typically form a ratio of wholenumbers. For example, in a reaction that forms ammonia (NH3), exactly one molecule ofNitrogen (N2) reacts with three molecules of Hydrogen (H2) to produce two molecules ofNH3: N2 + 3H2 → 2NH3Stoichiometry can be used to calculate quantities such as the amount of products (inmass, moles, volume, etc.) that can be produced with given reactants and percent yield(the percentage of the given reactant that is made into the product). Stoichiometrycalculations can predict how elements and components diluted in a standard solutionreact in experimental conditions. Stoichiometry is founded on the law of conservation ofmass: the mass of the reactants equals the mass of the products. Reaction stoichiometry describes the quantitative relationships amongsubstances as they participate in chemical reactions. In the example above, reactionstoichiometry describes the 1:3:2 ratio of molecules of Nitrogen, Hydrogen, andAmmonia. ÎÖ Chemistry Experiment’s
  58. 58. 57 Composition stoichiometry describes the quantitative (mass) relationships amongelements in compounds. For example, composition stoichiometry describes the Nitrogento Hydrogen (mass) relationship in the compound Ammonia: i.e., one mole of Nitrogrenand three moles of Hydrogen are in every mole of Ammonia. A stoichiometric amount or stoichiometric ratio of a reagent is the amount orratio where, assuming that the reaction proceeds to completion: 1. all reagent is consumed, 2. there is no shortfall of reagent, and 3. no residues remain.A non-stoichiometric mixture, where reactions have gone to completion, will have onlythe limiting reagent consumed completely. While almost all reactions have integer-ratio stoichiometry in amount of matterunits (moles, number of particles), some non-stoichiometric compounds are known thatcannot be represented by a ratio of well-defined natural numbers. These materialstherefore violate the law of definite proportions that forms the basis of stoichiometryalong with the law of multiple proportions.Material and apparatus50 ml beaker glass, ruler, CuSO4 0,1 M, NaOH 0,1 M.Procedures1. Provide two 50 ml beaker. Into a beaker enter 5 ml of 0.1 M NaOH on the other beaker insert 25 ml 0.1 M CuSO4 Combine the two solutions, then stir.2. Allow the mixture a few moments until the precipitate formed at the bottom of the beaker.3. Measure the height of sediment formed using a ruler (use units of mm).4. Perform the same manner as steps 1-3 for subsequent experiments by changing the volume of each reagent but still 30 ml total volume, as follows: 10 ml of 0.1 M NaOH and 20 ml of 0.1 M CuSO4 15 ml of 0.1 M NaOH and 15 ml of 0.1 M CuSO4 ÎÖ Chemistry Experiment’s
  59. 59. 58 20 ml of 0.1 M NaOH and 10 ml of 0.1 M CuSO4 25 ml of 0.1 M NaOH and 5 ml of 0.1 M CuSO45. Make a chart that states the relationship between the precipitate (Y-axis) and volume of each solution (X-axis), so it make two curves on one graph.6. From this graph determine the reaction coefficient based on the second cut point curve. Cutoff state reaction coefficient comparison.Analysis of data In the experiment above, the graph obtained from the data between the highdeposition of the volume of each reagent is determined by changing the reactionstoichiometry unit volume of each reagent having a mole intersection. Moles = molarity x volume of solutionThus obtained : mole ratio = ratio of the reaction coefficientQuestionsPre-lab questions1. Make it work steps in form of images on the lab journal2. Write down all the equations in these experimentsPost-lab questions1. Calculate the number of moles of sediment generated from each experiment2. Sodium sulfate tetrahydrate of 240 g containing 162 g of water crystals. Molecularformula is .... ÎÖ Chemistry Experiment’s
  60. 60. 59 OBSERVATION DATA SHEET Title : Date : Purpose : Sketches of procedure ObservationÎÖ Chemistry Experiment’s
  61. 61. 60Deposition reaction stoichiometry Exp.- Volume of NaOH 0,1 M Volume of CuSO4 0,1 M Precipitate height 1 2 3 4 5Reaction and calculations : ÎÖ Chemistry Experiment’s
  62. 62. 61Analysis of Data :Deposition reaction stoichiometry graphicConclusion : Jakarta, ..............................., 20.... Assistant ............................................... ÎÖ Chemistry Experiment’s
  63. 63. 62Purposes Colligative properties of solutions to experiment through trial decrease inHarnstoff solution freezing point.Overview Colligative properties of solution is the physical nature of the solution onlydepends on the number of solute particles and not depend on the type of solute. Areclassified as colligative properties of solutions are: decrease in vapor pressure, elevationof boiling point, freezing point depression and osmotic pressure of the solution. In thenature of the rise in boiling point and the colligative freezing point depression, the greaterthe molality of the solution, the higher rise in boiling point of the solution and the higherthe decrease in freezing solution. Therefore, the solution increases the boiling point (Tb)and a decrease in freezing solution (Tf), is directly proportional to the molality of thesolution. In the following experiments, will be tried as colligative properties of solutionfreezing point depression.Materials and apparatus Alat : Bahan : 500 ml beaker glass Harnstoff 100 ml beaker glass Ice cube Reaction tube Aquadest Thermometer Stopwatch ÎÖ Chemistry Experiment’s
  64. 64. 63Procedure 1. Enter as many as 50 ml of distilled water into a large test tube. 2. Enter the ice that has been crushed into a beaker approximately as high as the solution in a test tube (so the ice can cover the entire solution in a test tube). 3. Insert the thermometer into a test tube containing distilled water. Record the room temperature laboratory. 4. Prepare the stopwatch. Insert the tube into a beaker that has been filled ice cubes at the same time and also run the stopwatch. 5. Observe the temperature changes that occur every 30 seconds. Do it to show a constant temperature as much as three points. 6. Repeat steps 1-5 using a solution of harnstoff.Analysis of data From experiments on steps 1-5 for distilled water, make a graph of temperature(Y-axis) with time (X-axis). Create a chart is also to step 6 (Harnstoff solution).Pre-lab questions 1. What differentiates ordinary solution colligative properties colligative properties of electrolyte solutions with? 2. What is the freezing point of 0.2 m Potassium bromide in water if it is known freezing point of 0.1 m Sucrose solution in water is -0.18 º C.Post-lab questions 1. In the experiment above, why ice cubes should cover the entire solution? 2. Make a comparison of the temperature drop of urea solution at a constant point in the experiment with the urea solution freezing point of reference books available. 3. What is the boiling point of Magnesium chloride solution of 0.05 m in water if it is known boiling points of binary strong electrolyte is 0.25 m 100.26 º C. ÎÖ Chemistry Experiment’s
  65. 65. 64 OBSERVATION DATA SHEET Title : Date : Purpose : Sketches of procedure ObservationÎÖ Chemistry Experiment’s
  66. 66. 65Physical data of pure solvents and temperature measurement per 30 seconds Temperature and Solvent volume Mass (handbook) Corrected density room pressure Mass Times- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 T Times- 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 TPhysical data and temperature measurement solution per 30 seconds water Harnstoff Mass Molality Times - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 T Times- 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 TPhysical data and temperature measurement solution per 30 seconds water Harnstoff Mass Molality Times- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 T Times- 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 TCalculations : ÎÖ Chemistry Experiment’s
  67. 67. 66Analysis of Data :Graphic of temperature (Y-axis) with time (X-axis) ÎÖ Chemistry Experiment’s
  68. 68. 67Conclusion : TangSel, ................................... 20..... Assistant, ............................................ ÎÖ Chemistry Experiment’s
  69. 69. 68Purpose Understand the concept of equilibrium and the factors that influence it. Calculate the equilibrium constant prices based on experiments.Overview Chemical reactions are generally in a state of equilibrium. Reaction in equilibriumcan be known from the macroscopic properties (such as color, concentration, etc.) thatdo not change (at constant temperature) after reaching equilibrium conditions, butsymptoms did not change in the molecular two-way continuous. Macroscopic propertiesare most easily observed, to determine the system has peak at equilibrium conditions ornot, is the change in color of the solution. For example, if we dissolve the I2 preformancethen the water will initially yellow solution which formed the longer the color of thesolution becomes darker and finally dark brown. The color of the solution will not changeanymore while the process of molecular (crystal dissolution I2) persists but offset by re-crystal formation I2, therefore, after equilibrium is reached the number of crystals of I2 insolution is always fixed. This equilibrium condition can be influenced by several factors, including changesin temperature, change of pressure and concentration changes. Where these changes canlead to a shift in either direction toward reactant reaction and reaction products.In a chemical equilibrium system temperature relationship as simple artifacts betweenconcentration of reaction products and reactants concentration. For the general reaction: ÎÖ Chemistry Experiment’s
  70. 70. 69 aA + bB → cC + dDthen the temperature remains valid: , where K is the equilibrium constant.Methode At trial the determination of the equilibrium constant prices, will be studied reactionFe3+ + SCN- ↔ FeSCN2+ , where the concentration of each ion can be determinedby colorimetry. Determination in this way is based on the fact that the intensity of a beamof light through a colored solution, depending on the number of colored particles thatexist in the path of the light beam. Thus the intensity of this light should be proportionalto the concentration of solution and the path length of light beam. Color ≈ consentration (c) x height/width of solution chamber (d) color = k x c x d ; k = constant If we compare the kind of solution contained in two places (eg. tubes 1 and 2) thesame size but have different concentrations, then we can vary the amount of light beampaths to the same color intensity resulting from the second solution. In this conditionapplies: K x c1 x d1 = K x c2 x d2 c1x d1 = c2 x d2Materials and apparatusApparatus : 100 ml beaker glass, 10 ml measuring cylinder, 10 ml volumetric pipet, Testtube, Bigger test tube, Pipet.Materials : KSCN 0,002 M; Fe(NO3)3 0,2 M; NaH2PO4 0,2 M.Procedure Ferri(III) thiocyanate 1. Enter 10 ml of 0.002 M KSCN into a beaker, then add 2 drops Fe(NO3)3 0,2 M, then stir. 2. Divide the solution formed into 4 test tubes with an equal volume. Tube 1 as control ÎÖ Chemistry Experiment’s
  71. 71. 70 Tube 2 add 10 drops KSCN 0,002 M Tube 3 add 3 drops Fe(NO3)3 0,2 M Tube 4 add 5 drops NaH2PO4 0,2 M 3. Observe and note the changes occur from that reaction.Determination of equilibrium constant 1. Provide a 4 clean test tube (type and size of tube should be the same) and are numbered 1 through 4. 2. Insert the 5 ml of 0.002 M KSCN into each tube. 3. Into the tube 1 add 5 ml Fe(NO3)3 0,2 M save it as a standard. 4. Into a 100 ml beaker, put 10 ml of Fe (NO3)3 0.2 M and add distilled water until the volume of 25 ml (calculate the concentration of Fe3+). Pipette 5 ml of this solution and put into tube 2. The remaining solution will be used for the next step. 5. Take 10 ml of Fe(NO3)3 of the rest of the experiment step 4, add distilled water until the volume of 25 ml (calculate the concentration of Fe3+). Pipette 5 ml of this solution and put into the tube 3. The remaining solution will be used for the next step. 6. Do the same work as step 5 for the tube 4. 7. To calculate FeSCN2+ ion concentration, compare the color of the solution in tube 2 with tube 1 (as standard). Observations made by looking at the second color of the solution from the top tube (observations appear above). If not the same color intensity, remove the solution from the tube a drop by drop (in the capacity of the other test tube to be reused) until the second solution in the tube shows the same color. Measure the height of the two solutions with a ruler (in mm). 8. Do the same work as step 7 for the tubes 3 and 4 by comparing with the tube 1 (default). ÎÖ Chemistry Experiment’s
  72. 72. 71Analysis of dataCalculations for each tube : 1. On the tube to-1 considered all the thiocyanate ion has reacted to FeSCN2+. The solution in this tube is used as a standard. 2. Comparison of tube high = first tube height/tube height-n. 3. [FeSCN2+]equilibrate = comparison of tube height x [FeSCN2+]standard. 4. [Fe3+]equilibrate = [Fe3+]initial – [FeSCN2+]equilibrate . 5. [SCN-]equilibrate = [SCN-]initial – [SCN-]equilibrate . 6. Find a relationship that produces a constant value of the concentration of ions at equilibrium for the tubes 2, 3, and 4 by the following calculation: [Fe3+][FeSCN2+][SCN-] [Fe3+][FeSCN2+]/[SCN-] [FeSCN2+]/[SCN-][Fe3+]Pre-lab questions 1. Sketch the step of procedure on lab journal. 2. Calculate the concentration of Fe3+ and SCN at first in units of molar concentration of each reagent is inserted into the tubes 1, 2, 3 and 4.Post-lab questions 1. From the calculation step to-6 Which combinations of a, b, or c indicating the price constant or nearly constant? give an explanation. ÎÖ Chemistry Experiment’s
  73. 73. 72 OBSERVATION DATA SHEET Title : Date : Purpose :Equilibrium of Ferri(III) thiocyanate Sketches of procedure Observation ÎÖ Chemistry Experiment’s
  74. 74. 73Determination of equilibrium constant values Sketches of procedure Observation ÎÖ Chemistry Experiment’s
  75. 75. 74 3+ - [FeSCN2+]eq [SCN-]eq [Fe3+]eq Tube [Fe ]initial [SCN ]initial d1 / d x A B C 1 2 3 4 Tube AxBxC (A x B) / C A / (B x C) 1 2 3 4Calculations and reaction equations : ÎÖ Chemistry Experiment’s
  76. 76. 75Analysis of Data : ÎÖ Chemistry Experiment’s
  77. 77. 76Conclusions : TangSel, ...................................20..... Assistant, ............................... ÎÖ Chemistry Experiment’s
  78. 78. 77Overview Colloidal system (hereinafter abbreviated as "colloidal" only) is a form of themixture dispersion system) two or more substances that are homogeneous but have adispersed particle size is quite large (100-100 nm), thus exposed to the Tyndall effect.Means homogeneous dispersed particles is not affected by gravity or other forces appliedto him; so that no precipitation occurs, for example. Homogeneous nature is shared by thesolution, but not owned by usual mixture (suspension). Colloids easily found everywhere: milk, gelatin, ink, shampoo, and clouds areexamples of colloids that can be found daily. Cytoplasm in the cells is also a colloidalsystem. Colloidal chemistry were analyzed separately in the chemical industry because ofits importance. Colloids have a variety of forms, depending on the phase dispersed dispersingagents and substances. Several types of colloid: Aerosols are having a gas dispersing agents. Aerosol has dispersed liquid substance called liquid aerosols (eg, fog and clouds) while having a solid substance called aerosols dispersed solids (eg, smoke and dust in the air). Sol colloidal system of solid particles dispersed in liquid. (Example: The river, the soles of soaps, detergents and sol ink). Emulsion colloid system of liquid dispersed in another liquid, but the two liquids do not dissolve each other. (Example: coconut milk, milk, mayonnaise, and fish oil). Bubble Colloidal Systems of gas dispersed in liquid. (Example: on the processing of metal ore, fire extinguishers, and other cosmetics). ÎÖ Chemistry Experiment’s
  79. 79. 78 Gel system of rigid colloidal or semi-solid and half liquid. (Example: agar-agar, glue).Tyndall Effect Tyndall effect is the phenomenon ray scattering (light) by the colloidal particles.This is because the size of colloidal molecules are quite large. Tyndall effect wasdiscovered by John Tyndall (1820-1893), an English physicist. Therefore the nature of theso-called Tyndall effect. Tyndall effect is the effect that occurs if a solution is exposed to light. At the truesolution is irradiated with light, then the solution will not scatter light, whereas incolloidal systems, the light will be scattered. it happens because the particles are colloidalparticles having a relatively large to scatter light. Conversely, the true solution, theparticles are relatively small so that scattering occurs only a few and very difficult toobserve.Brownian motion Brownian motion is the movement of colloidal particles that always move straightbut erratic (random motion / irregular). If we observe under the microscope ultra colloid,then we will see that the particles will move to form a zigzag. Zigzag movement is calledBrownian motion. The particles of a substance in constant motion. These movements canbe random as in liquids and gases (called motion brown), whereas in solids onlyberoszillasi in place (not including the motion of brown). For colloids with mediumdispersing liquid or gas, the movement of particles will produce collisions with thecolloidal particles themselves. The collision took place from all directions. Therefore theparticle size small enough, then the collisions that occur tend to be balanced. So there is aresultant collision that causes change in direction of motion of particles resulting in azigzag motion or Brownian motion.Materials and apparatus : ÎÖ Chemistry Experiment’s
  80. 80. 79Materials : FeCl3; aquadest; agar-agar, gelatine, kerosene, protein flour, instant yeast,sugar, milk powder, butter, salt, sulfur powder, detergent.Apparatus : 100 ml beaker glass, alcohol burner, tripod, gauze, stir rod, analyticalbalance, spatula, mortal and pestle, test tube, oven, pan.Procedure :A. Preparation of Colloids by condensation1. Preparation of sol Fe (OH)3 Heat 50 ml of distilled water in a 100 ml beaker until boiling. Add 25 drops of saturated solution of FeCl3 and stir until the mixture while continuing warming red brown.B. Dispersion Method1. Preparation of sulfur sol Mix one gram of sulfur and sugar that is refined. Take the mixture and add one gram of sugar and Crush until smooth. Continue the work to four times. Put some final mixture into a glass cup containing 50 mL of distilled water and stir. Observe.2. Preparation of agar gel Fill a test tube with distilled water until the third. Add gelatin and stir, heat to boiling tube. Refrigerate the mix until it became gelatinous.3. Makers of oil in water emulsion Put about 5 ml of water and 1 ml of kerosene into a test tube. Shake the tube, and save it on the tube rack, observe what happens. Put about 5 ml of water, 1 mL of kerosene and 1 mL of detergent solution in another tube. Shake the tube, and store in a tube rack, observe that occurred. ÎÖ Chemistry Experiment’s
  81. 81. 804. How to make white bread: Enter the high protein flour, instant yeast, sugar, and milk powder, stirring until blended. Add water little by little and stir until the dough is rather dull. Add the white butter and salt, continue stirring until dough is dull. Round the dough and rest for 10 minutes. Divide the dough @ 450 grams and let stand for 15 minutes. Formed bread dough and place it in the bread pan was smeared with margarine. Let the dough (+ 90 minutes). Bake until cooked, brownish yellow (for temperature = 200 oC baked for 20 minutes).Question 1. Write the reaction that occurs in the manufacture of soles Fe(OH)3 ! 2. Explain the differences in the manufacture of colloids by means of condensation and dispersion !. 3. What substances are formed after burning gel Ca-Acetate ? ÎÖ Chemistry Experiment’s
  82. 82. 81 OBSERVATION DATA SHEET Title : Date : Purpose : Sketches of procedure ObservationÎÖ Chemistry Experiment’s
  83. 83. 82ÎÖ Chemistry Experiment’s
  84. 84. 83ÎÖ Chemistry Experiment’s
  85. 85. 84Reaction equations :Analysis of data : ÎÖ Chemistry Experiment’s
  86. 86. 85Conclusion : TangSel, .................................20.... Assistant, ....................................... ÎÖ Chemistry Experiment’s
  88. 88. 87SISTEMATIKA LAPORAN : 1. Judul percobaan 2. Tujuan percobaan 3. Pendahuluan/dasar teori 4. Alat dan bahan 5. Sketsa prosedur kerja dan pengamatan Sketsa prosedur kerja Pengamatan 6. Perhitungan dan persamaan reaksi 7. Analisis data 8. Pembahasan 9. Kesimpulan 10. Daftar pustaka (min. referensi dari tiga buku kimia tingkat universitas dan satu dari website/blog) ÎÖ Chemistry Experiment’s
  89. 89. 88ÎÖ Chemistry Experiment’s