...Jacinta Houng Comparing the Solubility of Chemicals in Water “Water is known as the “universal solvent” because so many different substances dissolve in it and we rely on this for many of our daily needs.” Introduction: Water is known as the ‘universal solvent’ as it is capable of dissolving a variety of different substances and dissolves more substances than any other liquid. However the ability to be soluble depends on a substances polarity and bonding. This then contributes to the various ways that different types of chemicals interact in water. Solubility is crucial to every living thing on earth as water can carry along valuable chemicals, minerals, and nutrients necessary for survival. In fact Water covers 70% of the Earths surface and composes 55-70% of the human body. Water is an excellent solvent due to its chemical composition and physical attributes. According to USGS (http://water.usgs.gov/edu/qa-solvent.html ) Water molecules have a polar arrangement of the oxygen and hydrogen atoms—one side (hydrogen) has a positive electrical charge and the other side (oxygen) has a negative charge. A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. This causes the molecule to have a slight electrical dipole moment where one end is slightly positive and the other is slightly negative. "Like dissolves like" is an expression used by chemists to help them remember how solvents work. The expression refers to...
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...experimentations were begun to determine the identity of the compound. Determining the identity of this compound was very crucial for the safety of the community. The chemical and physical properties of the compound could then be identified and environmental hazards addressed. Questions that needed to be answered in relation to this unknown compound included: Is it a risk to people living nearby? What if it gets in the water supply? Does it contaminate the air? Is it reactive? Over a three week time-span the chemists experimented with the unknown compound to report the findings back to the community. After the unknown compound was identified, the chemists studied its properties and confirmed the identity by synthesizing the compound in the lab and comparing it to the unknown. Experimental Week 1 After a sample of the unknown compound (#21) was retrieved, various experiments were carried out to determine the chemical formula. An anion analysis was first performed on the unknown compound. A solution of the unknown compound was prepared by taking a small amount of the solid on the end of a scoopula and dissolving it in 2 mL of distilled water (DI water) in a test tube. The compound was then tested for the sulfate ion by placing 1 mL of the solution in a test tube and adding 1 mL 6 M HCl and 1 mL of BaCl₂ solution. A white precipitate proves the presence of a sulfate ion. (aq) + (aq) (s) + 2 (aq) A carbonate ion analysis was also performed by adding 1 mL of the unknown solution...
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...Title: Experiment 9: LeChatelier’s Principle Purpose: The purpose of this lab is to delve into the concept of solubility and look at it as having more properties than just it’s soluble or no it’s not. Procedure: In this lab we will be using Le Chatelier’s principle to predict the effects of temperature, pressure, and concentration changes on a given system at equilibrium. I will account whether the process is endothermic or exothermic in the given direction when discussing temperature. Data tables and observations: Balanced Equations: Ca(OH)2 + 2HCl --> CaCl2 + 2H2O |Temperature |Average change in Vol.|[OH-] conc. (M) |Molar solubility |DG | |(Celsius) |(mL) | | | | |Ice (avg.9.25) |11.83 |59.2 |29.6 |-27.1 | |Room Temp. |10.54 |52.7 |26.4 |-27.6 | |30 |8.33 |41.7 |20.9 |-26.4 | |40 |9.64 |48.2 |24.1 |-28.5 | |50 |8.21 |41.1 |20.6 |-28.1 | |60 |7.15 |35.8 |17.9 ...
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...IB Chemistry Lab Report Design Example— Effect of Temperature on Solubility of Potassium Chloride in Water Research question How does temperature affect the solubility of potassium chloride in water? Hypothesis As the temperature of water increases, the particles of solid Potassium chloride, KCl, which are absorbing energy from its surrounding, start moving more easily between the solution and its solid state because. According to the second law of thermodynamics, the particles will shift to the more disordered, more highly dispersed solution state. I predict that as the temperature of a KCl and water mixture increases, then the solubility of the KCl will also increase. Variables Dependant variable The dependant variable will be the solubility of Potassium chloride in water that will be calculated at different temperatures. The solubility will change as temperature increases. Independent variable The control variables need to be constant in order to get valid and accurate results. The temperature of the solutions. Controlled variables The volume of distilled water used to dissolve Potassium chloride in each beaker The amount of Potassium chloride deposited into each beaker. The volume of the solution extracted by the syringe. Weight of each 50ml beaker Materials 6 Syringes 1 Heating plate 6 distinctly labeled 50ml Beakers 1 Electric Balance 6 Stirring Rods Distilled Water 6 distinctly labeled 100ml Beaker Controlling...
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...formula of acids and bases in order to understand how one substance will react with another. In this lab we observed how acids and bases change the color of certain dyes, such as litmus. We also observe the solubility of certain salt compounds. When solids dissolve in water, they dissociate to give the elementary particles from which they are formed. As a result, ionic solids dissociate to give solutions of the positive and negative ions they contain. Experiment Please refer to Report Sheet Calculations Please refer to Report Sheet for pH values of acid bases and salts utilized in the lab experiment Reaction of Salt mixtures FeCl3 + CoCl2 ( FeCl2 + CoCl3 Complete: Fe3+ + 3Cl- + Co2+ + 2Cl- ( Fe2+ + 2Cl- + Co3+ + 3Cl- Net: Fe3+ + Co2+(Fe2+ + Co3+ CoCl2 + Na2CO3 ( CoCO3 + Na2Cl2 Complete: Co2+ + 2Cl- + 2Na+ + (CO3)2- ( CoCO3 + 2NA+ + 2CL- Net: Co2+ + CO3 2- ( CoCO3 CuSO4 + Na2CO3 ( CuCO3 + Na2SO4 ionic: Cu+2 + SO4-2 + Na2+1 + CO3-2 ( CuCO3 + Na2+1 + SO4-2 Net: CO3- + Cu+ ( CuCO3 CuSO4 + Na3PO4 ( Cu3(PO4)2+Na2SO4 Complete:Cu+2 + SO4-2 + 6Na+ PO4(3-)+2 ( Cu3(PO4)2 + Na+ + SO4-2 Net: 3Cu(2+)+2PO4(3-) ( Cu3(PO4)2 Na3PO4(aq)+NiCl2(aq)->Ni3(PO4)2(s)+NaC Complete: Na+ + PO43- + Ni2+ + Cl- ( Ni3(PO4)2 + Na+ + Cl- Net: PO43- + Ni2+ ( Ni3(PO4)2 Discussion: Action of acids on Salts For a metal to react with an acid to form a salt and hydrogen gas, it has to be above hydrogen in the electrochemical series (ECS). The...
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...order to predict the pH of a solution containing a weak acid or base. • Demonstrate the use of common pH and redox indicators in microbiological media. • Select appropriate reagents to make a buffer having a desired pH. • Determine which compounds undergo the process of reduction and which undergo the process of oxidation. • Describe the basic chemistry of the predominant biologically important elements and their function(s) in microbiological systems. Dr. Andrew Baer Office Hours Monday: 10:30 am – 11:20 am Wednesday: 1:30 pm – 2:20 pm Thursday: 9:30 am – 10:20 am or by appointment Email: abaer@centennialcollege.ca Textbook: Hage, D.S and Carr J.D Analytical Chemistry and Quantitative Analysis, Prentice Hall, 2011 (optional) CH 125 Lab Manual (available on eCentennial) Additional References: Harris, Daniel C., Exploring Chemical Analysis, 5th Ed., W. H. Freeman and Company, 2012. Harvey, David, Analytical Chemistry 2.0 (Available Online – Link on eCentennial) Virtual...
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...Lab report for Experiment #2: Extraction Your Name: Name of TA: Lab Partner’s Name: Lab Section: Title: Experiment #2: Extraction Purpose: What is the purpose of this lab? In your OWN words! Observations: Weighed out 3.2568 grams of chemical mixture that was yellow in color. Dissolved dry chemicals in 38 ml CH2Cl2 with gentle heating. Poured the yellow solution into sep funnel. Added 10 ml CH2Cl2 to flask to rinse, poured solution into sep funnel. Added 15 ml 3 M HCl, gently mixed and vented (saw bubbles during mixing, heard the evolution of gas while venting). Allowed layers to separate. Upper layer determined to be aqueous by density: lower layer removed. Upper layer placed into separate flask labeled “A” for acid extract. Lower layer placed into sep. funnel and reextracted with 15 ml 3 M HCl. Combined aqueous layers in flask A Reextracted CH2Cl2 layer containg chemicals with 15 ml 3 M NaOH. Upper layer in flask labeled “B” for base extract. Re-extract organic layer with 15 ml 3M NaOH. Combined base extracted materials in flask “B”. Saw bubbles during mixing, heard the evolution of gas while venting. Dried organic layer with anhyd. Na2SO4 until free flowing salt was observed (about 3 grams). Filtered the organic solution into a tared 100 ml round-bottom flask. Rinsed flask and funnel with 10 ml of CH2Cl2 and rotovaped off remaining solvent and weighed flask. The biphenyl obtained was white in color and was like a powder. Weight of flask and biphenyl...
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...Coordinator : Dr Chee Swee Yong Lecturers : Ms Chang Chew Cheen, Dr Chee Swee Yong, Dr Lim Tuck Meng, Dr Sim Yoke Leng |Lab group |Lab A |Lab B | |Venue |D012A |D012B | |Monday @ 9.00 am – 11.30 am |P5 |P1 | |Monday @ 3.00 pm – 5.30 pm |P2 |P3 | |Wednesday @ 9.00 am – 11.30 am |P3 |P4 | |Wednesday @ 3.00 pm – 5.30 pm |P1 |P2 | |Thursday @ 3.00 pm – 5.30 pm |P4 |P5 | |Week |Experiment |Lab group |Lecturer | |1 |Briefing by HoD |Lab A/ Lab B |Dr Sim KM | | |Expt 1: Investigating the properties of Period 3 oxides |Lab A |Dr Chee SY | | | | | ...
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...experimental mass of alum was less than the theoretical mass was because of various errors in the lab. One possible error for this lab was the purity of the aluminum can. The cans had to have the inside and the outside of them scraped with steel...
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...Mystery Substance Lab Write-Up The haters always say, “Johnny, you’re bad at chemistry.” Well, this lab proved the haters wrong. Charlie and I were the first in our class to guess the mystery substance correctly, (we hope), and we did it while doing the fewest tests (we think). “That’s a weird brag,” the haters would say. I think they’re just jealous. The goal of this lab was to find out as much as possible about the given mystery substance. Charlie and I did that, and more. As I said earlier, we were even able to identify with almost complete certainty what our substance was: ammonium acetate. In general, Charlie and I tried to be as thorough as possible with the tests without being redundant. For example, since we were certain that the substance was an acetate after doing a number of solubility tests, we decided not to do experiments that tested for a sulfate or something else of that nature. Besides trying to avoid redundancy, we also tried to maintain calm, even when a test didn’t go the way...
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...mechanism and action of buffers in maintaining the proper pH in health and in disease states. Definitions (Review of basic concepts) 1. Acids: Compounds that release hydrogen (proton donors) 2. Bases: Compounds that accepts hydrogen (proton acceptor) 3. Strong Acids: Compounds with weak affinity to H+ (release all H+ ions) 4. Strong Base: Compounds with strong affinity to H+ (Bind H+ ions) 5. The dissociation constant K: It reflects the strength of an acid or base. The larger the K value, the greater the dissociation of H+ ions, thus the stronger the acid. 6. pK: is the negative log of K. The smaller the pK the stronger the acid (Strong acids has a pK 9.0) 7. Buffers: A combination of weak acid and its conjugate base (salt). It resists change of pH upon addition of small amounts of strong base. 8. The Handerson-Hasselbalch equation: It governs the mechanism of a buffer system. For the weak acid HA, it dissociates as follows: HA -----------> H+ + A- The Handerson-Hasselbalch equation is written as follows: A- pH = pK +...
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...Double Displacement Reactions and Solubility 1. Write the balanced molecular equations for the reactions where the following occurred: a)Fe+3 precipitated b) Co+2 precipitated Answer: a) Fe+3 precipitated Fe(No3)3 (Aq) + 3NaI(Aq)---> FeI3(s) + 3NaNO3(aq) Fe(No3)3 (aq)+3NaBr (aq)---> FeBr3 (s) +3NaNo3(aq) Answer: b) Co+2 precipitated Co(NO3)2 (aq)+ 2NaOH ¬(aq) ---> Co(OH)2 (s)+ 2NaNO3(aq) 2. Consult your results table and write Net Ionic equations for the all of the reactions where silver precipitated out of the solution. Answer: Ag+ + Cl- ---> AgCl(s) Ag+(aq) + I+(aq) --->AgI(s) 3 Ag (aq)+ (PO4)3(aq) --->Ag3PO4(s) Ag(aq) + OH(aq)- ---> AgOH(s) 2Ag(aq) + CO3(aq) ---> Ag2CO3(s) 2Ag(aq) + SO4(aq) ---> Ag2SO4 2Ag...
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...The SN2 reaction can be evaluated by first observing the chemical mechanisms of the compounds involved. The agents took into account for the mechanism was the naphtholate anion and allyl bromide. First, a pair of lone pairs on the oxygen anion on the naphtholate compound attacks a single-bonded carbon on the allyl bromide compound. Afterwards, the bromide leaving group exits the allyl bromide compound, and creates its own anion cloud. Overall, this synthesizes naphthyl ether. The mechanism cannot be successfully accomplished without the input of the phase transfer catalyst. In the lab, the benzyl tri-n-butylammonium chloride acts as the phase transfer catalyst. As a phase transfer catalyst, it has the ability to transfer a reactant between...
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...Chemistry 1B Experiment 16 77 16 Qualitative Analysis Introduction The purpose of qualitative analysis is to determine what substances are present in detectable amounts in a sample. This experiment has two parts. In the first part, you will analyze an unknown solution for the presence of seven common ions. In the second part, you will test an unknown solid to determine which of two possible identities is correct. Part I. Spot Tests for Some Common Ions A simple approach to the qualitative analysis of an unknown solution is to test for the presence of each possible ion by adding a reagent which will cause the ion, if it is in the sample, to react in a characteristic way. This method involves a series of “spot” tests, one for each ion, carried out on separate samples of the unknown solution. The difficulty with this way of doing qualitative analysis is that frequently, particularly in complex mixtures, one species may interfere with the analytical test for another. Although interferences are common, there are many ions which can be identified in mixtures by simple spot tests. In this experiment we will use spot tests for the analysis of a mixture which may contain the following commonly encountered ions in solution: CO32– SO42– PO43– SCN Cl – – carbonate sulfate phosphate thiocyanate chloride acetate ammonium C2H3O2– NH4+ 78 Chemistry 1B Experiment 16 The procedures we involve simple acid-base, precipitation, complex ion formation or oxidation-reduction...
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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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