...Precipitation Reactions 2-4: Precipitation Reactions 1. Start Virtual ChemLab and select Reactions and Stoichiometry, and then select Precipitation Reactions from the list of assignments. The lab will open in the Inorganic laboratory. 2. React each of the cations (across the top) with each of the anions (down the left) according to the data table using the following procedures: Data Table | |AgNO3 (Ag+) |Pb(NO3)2 (Pb2+) |Ca(NO3)2 (Ca2+) | |Na2CO3 (CO32-) |A cloudy peach color peach |f. a milky white color |K a milky white color | | |color | | | |Na2S (S2-) |B a cloudy black color |G a cloudy black color |L no reactions | |NaOH (OH-) |C a cloudy bubbly brown color |H no reactions |M a milky white color | |Na2S04 (SO42-) |D no reactions |I turned a milky white color |N no reactions | |NaCl (Cl-) |E a milky white color |J turned a milky white color |O no reaction | a. Drag a test tube from the box and place it on the metal test tube stand. You can then click on the bottle of Ag+ ion solution...
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...Stoichiometry ________________________________________ Stoichiometry is simply the math behind chemistry. Given enough information, one can use stoichiometry to calculate masses, moles, and percents within a chemical equation. ________________________________________ ________________________________________ What is a Chemical Equation? In chemistry, we use symbols to represent the various chemicals. Success in chemistry depends upon developing a strong familiarity with these basic symbols. For example, the symbol "C"represents an atom of carbon, and "H" represents an atom of hydrogen. To represent a molecule of table salt, sodium chloride, we would use the notation "NaCl", where "Na" represents sodium and "Cl" represents chlorine. We call chlorine "chloride" in this case because of its connection to sodium. You should have reviewed naming schemes, or nomenclature, in earlier readings. A chemical equation is an expression of a chemical process. For example: AgNO3(aq) + NaCl(aq) ---> AgCl(s) + NaNO3(aq) In this equation, AgNO3 is mixed with NaCl. The equation shows that the reactants (AgNO3 and NaCl) react through some process (--->) to form the products (AgCl and NaNO3). Since they undergo a chemical process, they are changed fundamentally. Often chemical equations are written showing the state that each substance is in. The (s) sign means that the compound is a solid. The (l) sign means the substance is a liquid. The (aq) sign stands for aqueous in water and means...
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...I can remember him doing all kinds of experiments in his office trying to test and discover things that really drew my interest to this major. My grandfather demonstrated the benefits of Chemistry and showed me how it is ever present in our every day life. He also taught me that Chemistry is always changing in our world around us and I want to be apart of this changing process and help the world benefit from Chemistry. I hope to see myself in a couple years being highly successful and enjoying working for a refinery as my grandfather did. I want to be able to support my family the best as possible, yet I also want to see myself loving what I do everyday and not get tired of it. In Lab #1 it was a recap of math skills that are crucial for the basis of general Chemistry. This particular lab we touched base on the rules of significant figures in calculating different formulas. Also, rounding...
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...Lab: STOIOCHIOMETRY OF A PRECIPITATION OF REACTION By: Ruth Pierre 6/1/15 PURPOSE Stoichiometry is a section of chemistry that involves using relationships between reactants and products in a chemical reaction to determine desired quantitative data. Stoichiometry means the measure of elements. In order to use stoichiometry it is important to understand the relationships that exist between products and reactants and why they exist, which require understanding how to balanced reactions. The purpose of this experiment is to predict the amount of product produced in a precipitation reaction using stoichiometry. This experiment will also to determine the actual yield versus the theoretical yield in order to calculate the percent yield. MATERIALS * Distilled water * Paper towels * Small paper cup * Coffee cup or mug * Beaker 100 ml glass * Funnel * Cylinder 25 ml * Goggles for safety * Scale Digital-500g * Weighing boat plastic * CaCl2·2 H2O-Calcium Chloride, Dihydrate - 2.5 g * Filter Paper 12.5-cm, Na2CO3 -Sodium Carbonate - 2 g PROCUDURE 1. Put on your goggles. 2. Weigh out 1.0 g of CaCl2·2H2O and put it into the 100-mL beaker. Add 25 mL of distilled water and stir to form the calcium chloride solution. Use only distilled water since tap water may have impurities that interfere with the experiment. 3. Use stoichiometry to determine how much Na2CO3 you will need for a full reaction. 4. Weigh the calculated...
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...[pic] Official TCC Course Syllabus |Discipline Prefix: CHM |Course Number: 111 |Course Title: College Chemistry I | | |Course Section: D04B | | |Credit Hours: 4 |Lecture Hours: 3 |Clinical Hours: |Lab Hours: 3 | |Contact Hours: 6 |Studio Hours: N/A |Semester: Fall | |Meeting Days/Time/Location: Fridays/1:30pm-4:20pm/Science Building | Instructor Information Name: Dr. Shahin Maaref Office Location: JD-30 Office Hours: TRF 9:00am-11:00am, TR 4:30pm-5:30pm & by appointment Contact Information: 822-7692 Blackboard site: http://learn.vccs.edu Instructor email address: smaaref@tcc.edu Course Information Course Description Explores the fundamental laws, theories, and mathematical concepts of chemistry. Designed primarily for science and engineering majors. Requires a strong background in mathematics. Part I of II. Prerequisites and/or Co-requisites Prequisites - None Corequisites – None It is recommended to have H.S. chemistry or CHM01 as prerequisites and MTH 03 or MTE 06 level or higher. ...
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...Percentage of Oxygen in Compound-Stoichiometry/ Catalysis Page 2 Table of Contents Introduction Page 3 Experimental Procedure Page 4- 5 Results Page 6-7 Discussion Page 7 References Page 8 Page 3 Introduction This laboratory the weighting techniques and the use of stoichiometry to calculate percentages of substances were reviewed. To calculate the percent purity of sample, stoichometry relationships were used. In this lab stoichiometric relationship was use to find the percent of oxygen in potassium chlorate and also the percent purity of a sample provided. By definition, Stoichiometry is the quantitative relationship amongst elements in a compound to reactant ratio during a chemical reaction. Potassium chlorate (KClO₃), like many other oxygen composing compounds, is decomposed well by heat. Essentially there is an endothermic reaction that by the aid of a catalyst and heat will produce potassium chloride and oxygen. This equation looks as follows: KClO₃sMnO₂heat2KCls+3O₂(g) This process can happen without the presence of manganese dioxide (MnO₂), but it will take a very long time. Instead, MnO₂ is used as the catalyst to expedite the heating temperature and does not contribute to the overall oxygen output Page 4 Experimental procedure First, obtain two clean and dry 25x200mm Pyrex test...
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...239 #51-60 (odd) | 3 | Unit Conversions | Moles! Moles! Moles! LabPink and yellow cardsPg 242 # 61-70Pg 243 # 1-16 and Chapter Review (select your own) | 4 | Multistep conversionsQUIZ | * Mole Recipies * Mole Road Map index card * Have them pick what they want to bake and they get half a period to work on conversions and then the weekend to bake. Bring in milk for us to enjoy with our cookies. | 5 | Percentage Composition | Read pgs 258-261Chewing Gum LabDry Lab pg 260Pg 260 # 1-10 (even)Pg. 262 # 1-6 | 6 | Empirical Formula | Nut boltide labRead pgs 268-270Pg 270 # 7, 9, 12Read pgs 271-276Do # 31-40 (even) pg 275 | 7 | Combustion Analysis type problem and Hydrate Lab Prep | Pg 277 # 16, 17, 18 (Pre-lab) + data table for 3 hydrates | 8 | Mole Airlines flight 1023 | Work in groups of 4 and hand in at the end of the period with full calculations and ID chart filled outPg 225 # 41-47 (odd)Pg 278 # 51-60 (even)Pg 279 # 1-16 (all) | 9 | Problem Set on Empirical Formula and % Composition | Work in pairs and set up a solutions gallery with chart paper solutions in review for their quizQUIZ | 10 | Stoichiometry | Bicycle Activity – IntroRead pgs 296-299Pg 298 # 1-10 (odd)Pg 299 # 1-6 (even)Pg 300 # 11-20 (odd) | 11 | Chalk Lab | Activtiy 7.1 pg 301Mole MethodRead pgs 301-304 Pg 304 #21-30 (even)Pg 305 # 1, 4, 6, 7,10, 11 | 12 | Limiting Reagent Problems | Socratic – full step by step with a problemRead pgs 306-308Pg 309Do # # 31-39 (even) (practice)Do # 8, 10...
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...dissolved 3. 4.0g of sodium phosphate was added to a clean 150ml beaker and 50ml of distilled water was added. The solution was stirred until dissolved 4. I then poured the sodium phosphate solution into the beaker containing the zinc acetate solution. A white precipitate of zinc phosphate was formed in the beaker. 5. I then tried to filter all of the zinc phosphate through filter paper. It was a Friday and I didn’t get to finish so my experiment stayed in the lab with a glass cover over the weekend. 6. The following class I began to filter and some of the solution started dripping down the side of the beaker so I rinsed it with distilled water into the filter. Other debris that may have been collected on the side of the glass over the weekend could have also been filtered causing my experimental mass to be higher. 7. After filtered the filter paper with the solution was placed in a warm oven to dry over night. Conclusion: My results were clearly off from what they should have been. The predicted mass of the zinc phosphate was a little more then 50% off from the actual mass. A reason for this could have been a miscalculation on my part, but I believe I had the right masses in my stoichiometry equation (page before data table). The actual mass may also have been off because I had to leave my experiment in the lab for several days, so some sort of debris may have gone into the...
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...2-4: Precipitation Reactions 1. Start Virtual ChemLab and select Precipitation Reactions from the list of assignments. The lab will open in the Inorganic laboratory. 2. React each of the cations (across the top) with each of the anions (down the left) according to the data table using the following procedures: Data Table | |AgNO3 (Ag+) |Pb(NO3)2 (Pb2+) |Ca(NO3)2 (Ca2+) | |Na2CO3 (CO32-) |A NR |F Milk color |K Milk color | |Na2S (S2-) |B dark grey |G Dark grey |L NR | |NaOH (OH-) |C light grey |H NR |M Milk color | |Na2S04 (SO42-) |D NR |I Milk Color |N NR | |NaCl (Cl-) |E milk color |J Milk color |O NR | a. Enter the stockroom by clicking inside the Stockroom window. Once inside the stockroom, drag a test tube from the box and place it on the metal test tube stand. You can then click on the bottle of Ag+ ion solution on the shelf to add it to the test tube. Click Done to send the test tube back to the lab. Click on the Return to Lab arrow. ...
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...the endpoint of the reaction. Data collected from the titrations will be used to calculate the mass of the sodium hypochlorite in an unknown solution of bleach. Given the original mass of the unknown solution and the calculated mass of the sodium hypochlorite in the unknown solution, the percent by mass of the sodium hypochlorite can be determined. The oxidizing capacity of the unknown bleach is effectively the percent by mass of the sodium hypochlorite in the unknown bleach sample. OJECTIVES 1) Titration of a sample of bleach with thiosulfate. 2) Determining the end point of the titration with starch indicator. 3) To determine oxidizing capacity of bleach by determining the percentage by mass of the bleach that is sodium hypochlorite. 4) Balance and summarize the two redox reactions to determine the overall chemical reaction that occurs during the titration. PRINCIPLES Oxidizing Capacity of Bleach The effectiveness of a bleach to whiten and remove stains in white clothing is related to the oxidizing (bleaching) strength of an oxidizing agent, such as OCl−, which is found in common household bleaches. The hypochlorite ion is generally present as a sodium salt, NaOCl, or a calcium salt, Ca(ClO)2. There are two redox...
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...CaCl2(aq) Beaker (250 mL) Wash Bottle (distilled H2O) Filter paper Funnel Iron ring Ring stand Procedure: Part I: The Precipitation Reaction (Day 1) 1. Obtain two clean, dry 25 mL graduated cylinders and one 250 mL beaker. 2. In one of the graduated cylinders, measure 25 mL of the Na2CO3 solution. In the other graduated cylinder, measure 25 mL of the CaCl2 solution. Record these volumes in your data table. 3. Pour the contents of both graduated cylinders into the 250 mL beaker and observe the results. Record these qualitative observations in your observations table. Allow the contents of the beaker to sit undisturbed for approximately 5 minutes to see what happens to the suspended solid particles. Meanwhile, proceed to step 4. 4. Obtain a piece of filter paper and put your initials and your partner’s initials on it using a pencil. Measure and record the mass of the filter paper, then use it to set up a filtering apparatus. 5. Gently swirl the beaker and its contents to suspend the precipitate in the solution, then pour it carefully and slowly into the filter funnel. It takes time to complete the filtering process so plan to do it in stages. Use the wash bottle to rinse the remaining precipitate form the beaker into the funnel. 6. Use the wash bottle one last time to...
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...FHSC1114 Physical Chemistry 2014/05 Ms Azlina Banu, Mr Tam Yun Hong, Ms Chong Pui Kuan, Ms Amelia Chiang Kar Mun, Ms Farhanah, Ms Wong Jing Tyng, Ms Jamie Anne, Ms Lau Mei Chien, Mr Ng Sweet Kin, Ms Phang Ying Ning, Ms Precilla, Ms Rachel Tham, Ms Rajalakshmi, Mr Tan Jun Bin, Ms Tan Lee Siew Tutorial 3 : Chapter 3 Stoichiometry and Solution Concentration 1. Balance the following equations: (a) Al(s) + NH4ClO4(s) → Al2O3(s) + AlCl3(s) + NO(g) + H2O(g) (b) GaBr3(aq) + Na2SO3(aq) → Ga2(SO3)3(aq) + NaBr(aq) 2. Ethanol, C2H5OH, is a liquid with a density of 0.789 g ml-1 at 25 °C. Calculate the molarity of ethanol solution made by dissolving 20.00 mL of ethanol at 25 °C in enough water to make 250.0 ml of solution. [Ans: 1.37 mol L-1] 3. Copper sulfate is widely used as a dietary supplement for animal feed. A lab technician prepares a “stock” solution of CuSO4 by dissolving 79.80 g of CuSO4 in enough water to make 500.0 mL of solution. (a) Determine the molarity of the CuSO4 “stock” solution prepared by the technician. [Ans: 1 mol L-1] (b) Calculate the volume of CuSO4 “stock” solution that should be diluted to give 2.5 L of [Ans: 0.25 L] 0.1 M CuSO4. 4. Aluminum is a limiting reactant in the reaction with sulfur gas to form aluminum sulfide. Initially, 1.18 mol of aluminum and 2.25 mol of sulfur are combined. 2Al(s) + 3S(s) → Al2S3(s) (a) Calculate the aluminum sulfide formed in moles. (b) Calculate the mass of the excess reactant after the reaction. [Ans: 0.59 mol] [Ans:...
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...CHAPTER 3 MASS RELATIONSHIPS IN CHEMICAL REACTIONS This chapter reviews the mole concept, balancing chemical equations, and stoichiometry. The topics covered in this chapter are: • Atomic mass and average atomic mass • A vogadro’ s number, mole, and molar mass • Percent composition calculations • Empirical and molecular formula determinations • Chemical equations, amount of reactant and product calculations • Limiting reagents and reaction yield calculations Take Note: It is absolutely essential that you master the mole concept to do well on the quantitative aspects of AP Chemistry!! When solving quantitative problems on the Free Response section of the AP exam, supporting work must be shown to receive credit. Using dimensional analysis is a very powerful technique in solving problems. Be sure to report your answer to the correct number of significant figures (see Chapter 1 in this review book). Atomic mass and average atomic mass Atomic mass is the mass of an atom in atomic mass units (amu). One amu is defined as 1/12 of one C-12 atom. The C-12 isotope has a mass of exactly 12.000 amu. The C-12 isotope provides the relative scale for the masses of the other elements. Average atomic mass is the value reported on the periodic table, which takes into account the various isotopes of an element and their respective frequencies. To calculate the average atomic mass of an element, add up the different masses of the isotopes (using amu) multiplied by each isotope’s abundance...
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...Lab Report 2 – Titration CHEM1903 – Chemistry 1A (SSP) Michael West (305159240) 1. Experiment 2.2 – Titrimetric determination of the molecular mass of an organic acid Method An unknown organic acid was supplied in solid form. The acid was known to be diprotic and had the reference number 19. Using an analytical balance, 1.5397 g of the acid were weighed out, and made up with deionised water into 250 mL of solution. 25 mL of the acid solution was added to a conical flask with phenolphthalein indicator and titrated against standardized 0.0983 M NaOH solution. Three titrations were performed and the results averaged. The molar mass of the acid was then calculated and compared to a list of given possibilities. Results and Calculations The three titres were 26.30 mL, 26.50 mL and 26.30 mL. The mean titre volume was hence 26.37 mL. The number of moles of NaOH was thus moles. Because the acid was diprotic, reaction stoichiometry dictates that there was one mole of acid for every two moles of NaOH. Accordingly, in 25 mL of the acid solution, there were moles of acid. The molar mass of the acid is then g⋅mol-1. This matches most closely with succinic acid, for which the given molar mass was 118.1 g⋅mol-1. Although this represents a 0.6% discrepancy, the error is small enough to identify the acid as succinic acid with a high degree of certainty, given the possibilities listed. 2. Experiment 2.3 – Determination of the carbon dioxide and hydrogencarbonate contents of soda water...
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...Titrations Revisited By Drew Rutherford Concordia College Introduction The first experiment today will be the titration of acetic acid in vinegar. Vinegar is a solution of acetic acid, an organic acid of formula CH3COOH (MW = 60.0526 g/mole). In order to be sold as vinegar, it needs to meet the FDA’s guideline of 5.00% acetic acid by mass. Knowing that the density of vinegar is 1.04 g/mL and analyzing this solution by titration, chemists can determine the mass percentage of acetic acid in a sample of vinegar. The titration reaction is given below: CH3COOH + NaOH ( CH3COONa + H2O Reaction 1 A customer has purchased a vinegar solution at a local thrift store at a 20% discount and he believes that the sample of vinegar he has purchased does not meet FDA regulations. He is suing the thrift store for the $0.36 he feels that he has been cheated out of. The court has asked you to analyze the sample and render your verdict. Does this sample conform to the FDA guideline? If 2.00 mL of the thrift store vinegar required 9.73 mL of 0.150 M NaOH to reach the endpoint, then 0.00877 g of acetic acid was present. 9.73 mL NaOH x 1 liter NaOH x 0.150 mole NaOH x 1 mole CH3COOH x 60.0526 g CH3COOH 1000 mL 1 liter 1 moles NaOH 1 mole CH3COOH = 0.0876 grams CH3COOH in sample 2.00 mL vinegar x 1.04 g vinegar = 2.08 g vinegar 1 mL 0.0876 g CH3COOH x 100 = 4.21 % CH3COOH by mass 2...
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