The melting point range is defined as the span of temperature from the point at which the crystals first begin to liquefy to the point at which the entire sample is liquid. This data can be tabulated experimentally through multiple trials for an unknown and referenced against the chemistry literature for a known compound. In Macroscale and Microscale Organic Experiments‚ 5th ed‚ Williamson notes that most pure organic solids will melt repeatedly over a narrow temperature range of 1°C. As a measure
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Determining the unknown concentration of HCl via heat of neutralization of a reaction involving strong electrolytes and weak electrolytes. Myeongwon Lee 20522885 Partner: Frank Wong TA: Afsoon CHEM 120L – Earth Science & Chem 149 Section: 004 Tuesday‚ November 26th‚ 2013 Introduction All chemical changes are accompanied by change in energy and this energy is in form of heat. The energy change of a reaction that happens at constant pressure is defined as heat of reaction or enthalpy change and the
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TITLE : * Analysis of an unknown acetic acid solution OBJECTIVES : * To prepare the sodium hydroxide solution‚ NaOH * To standardise the base against potassium hydrogen phthalate * To analyse the unknown acetic acid RESULTS : A. Preparation of the sodium hydroxide solution Volume of NaOH taken from the stock solution = 3.33 mL B. Standardisation of the base against potassium hydrogen phthalate | 1 | 2 | 3 | Weight KHP | 1.0000 | 1.0004 | 1.0006 | Final volume
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Unknown 2 Scheme “ Fair game” ions Cations: Na+‚ K+‚ NH4+ ‚ Ca2+‚ Mg(OH2)62+ ‚ Al(OH2)63+ Anions: SO42-‚ HSO4-‚ NO3-‚ OH-‚ Cl-‚ CO32-‚ HCO3- Insoluble Compounds: Ca(OH)2‚ CaSO4•2H2O‚ CaCO3‚ MgCO3‚ Mg(OH)2 I. Describe Sample a. Quick description of sample. Ex: Phase‚ color‚ odor‚ crystalline‚ amorphous‚ gel-like‚ powdery‚ etc. II. Flame Test a. Part 1 i. Orange Flame: Na+ is present. K+ ‚ NH4+ ‚ Ca2+‚ Mg(OH2)62 ‚ Al(OH2)63+ may also be present. ii. Purple Flame: K+ is present (no Na+
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The poem the unknown citizen written by w.h Auden portrays from the point of view of the government what or how an ideal citizen should look like. This piece is written in third person omniscient to project a non-bias perspective and that way transmit the “truth” without being affected by feelings or personal point of views. Moreover at the end of the poem the author makes a relevant turn which effect is making the reader question himself if what was depicted before is the right thing‚ if that ideal
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bath for 10 minutes. The aspirin was collected by vacuum filtration. After it dried‚ it yielded 0.93 g (30.9 % of original Panacetin). Isolation of Unknown: 71 mL of boiling H2O were poured int an Erlenmeyer flask with 0.93 g of unknown to dissolve it. After reaching room temperature‚ the flask was placed into a bucket with ice and DI H2O. The unknown was collected by vacuum filtration‚ rinsed with ice water‚ and dried to constant mass at 0.72 g. 13C NMR (100.13 MHz‚ acetone-D6): σ 15.5 (s‚ Me)
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we know that we know. There are known unknowns. That is to say there are things that we now know we don’t know. But there are also unknown unknowns. There are things we do not know we don’t know. So when we do the best we can and we pull all this information together‚ and we then say well that’s basically what we see as the situation‚ that is really only the known knowns and the known unknowns. And each year‚ we discover a few more of those unknown unknowns.” I would have told you that I thought
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Lillian Zhang AP Chemistry 3rd Period Formula of an Unknown Hydrate The purpose of the Formula of an Unknown Hydrate lab is to determine the weight percentage of H2O hydrated to an unknown salt and the empirical formula for the hydrated salt. To do this‚ a massed amount of the hydrate is heated over either a hot plate or Bunsen burner. This causes the water to be removed‚ leaving the anhydrous salt behind in the dish. The mass of the anhydrous salt‚ now with the absence of water‚ is less than
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involves two oxidation-reduction reactions to calculate the oxidizing capacity of a sample of unknown bleach. In order to determine the volume of Na2S2O3 added‚ students will conduct a titration of bleach with thiosulfate with addition of a starch indicator to find the end point of the titration. Moreover‚ the oxidizing capacity of bleach is calculated with the percentage by mass of NaOCl in the unknown bleach sample. The overall chemical reaction throughout the experiment will be balanced with the
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many class lab days‚ I concluded my unknown was Calcium Carbonate due to results from the Flame Test and Anion I Test. Throughout our lab days‚ my friends would help me determine various odors and colors of the substances which allowed me to confirm my answer. Also‚ I looked select test results up on the internet to see if they matched my observations. On our first lab day‚ I received my bottle and noticed a white precipitate in the bottom therefore‚ my unknown was insoluble. I started my testing
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