Section 1: Purpose and Summary . Less moles of magnesium sulfate in the beaker would have then increased the ratio as the number of water moles would have been divided by a smaller value. \[x = \frac{n_{\ce{H2O}}}{n_{\text{Anhydrous Solid}}} \label{6}\], DO NOT perform any lab work outside of the stated lab hours. Continue heating gently until the salt turns completely light grey. If not enough heat is applied, some water will remain attached to the copper sulfate producing a low calculated mass percent water for the hydrate. The theoretical (actual) percent hydration (percent water) can be calculated from the formula of the hydrate . Once we know how much water is needed for each magnesium sulfate, we can then name the substance in MgSO 4 x H 2 O, where x represents the ratio. Includes teacher instructions, sample calculations, and, key to the conclusion questions. Magnesium sulfate, the only left option, is white in appearance which makes it a possible identification for our hydrate. represents the ratio. From the data the students can determine the experimental percentage of, list of six hydrated names that are provided, the students will write the formulas for those hydrates, calculate the theoretical percentage of, each, and determine which of the six hydrates is the identity of the unknown, Experiment for Stoichiometry! I give you teacher set up instructions, has an introduction to help students understand why they are doing the, from copper (II) sulfate pentahydrate by heating and determine the empirical formula. The error being only 5.58%, the overall ratio of water to magnesium sulfate was somewhat accurate. Describe what happens in your lab notebook. You'll get a detailed solution from a subject matter expert that helps you learn core concepts. Since copper (II) sulfate is usually a bright blue due to Cu. Then determine the molar mass of the whole hydrate (ionic compound plus water). We are given the following data in the trial 1 , Before Heating : Mass of Dry crucible and cover = 40.11 g Mass of crucib, Lab 5 Data Sheet: Percent Water in a Hydrate Name: British lue Date: 10.0% 2020 Instructor Time & Day of lecture online DATA TABLE Sample Identification Number Before Heating Trial 1 Trial 2 Trial 3 Mass of Dry Crucible and Cover a 40.11a b Mass of Crucible, Cover, and Hydrate 40:91009 Mass of Hydrate ba After Heating a Mass of Crucible, Cover, and Dry Solid 41.4809 e Mass of Anhydrous Compound da f Mass of Water in Hydrate Sample Trial 1 Trial 2 Trial 3 Calculate the percent of water in the Hydrate Sample Trial 1 Answer: Show calculations: Trial 2 Answer: Show calculations: Many compounds form from a water (aqueous) solution. The mass of water evaporated is obtained by subtracting the mass of the . Our unknown hydrate may be a hydrate of copper(II) sulfate, magnesium sulfate, iron(III) chloride, or iron(III) nitrate. Masses are measured beforeheating to determine the mass of theoriginal sample (the hydrate)andafterheating to determine the mass of copper (II) sulfate (CuSO4) anhydrous. What errors would this cause in the calculation of the percent of water in the hydrate? Iron (III) chloride usually has a bright yellow appearance. Once we know how much water is needed for each magnesium sulfate, we can then name the substance in MgSO. Mass of anhydrous salt Calculations - Remember to show all of your work. xH2O). If we had either heated the beaker with a strong flame from the beginning or increased the amount of time of heating, the number of moles of water during calculation could have been larger. The number of moles of water in a hydrate was determined by taking the mass of the water released and dividing it by the molar mass of water. GCC CHM 090 GCC, 2006 1 of 2 Names: _____ Lab Exercise: Percent Water in a Hydrate Introduction: A hydrate is a crystalline solid that traps water as part of its crystal structure. I ; O j CJ OJ QJ U56OJ QJ \] 56CJ OJ QJ \] j CJ OJ QJ CJ H*OJ QJ CJ H*OJ QJ 5>*CJ OJ QJ \5CJ OJ QJ \ CJ OJ QJ 6CJ OJ QJ ]: m n * M N Z } ~ ( dh &. The difference between these two masses is equal to the mass of the water lost. Sometimes the water is liberated in stages, with one or more lower hydrates being observed during the heating process. Your Lab Reports are individual assignments, but you're welcome to communicate with your group and discuss the results. Write the formula of the one you chose. Cross), Civilization and its Discontents (Sigmund Freud), Chemistry: The Central Science (Theodore E. Brown; H. Eugene H LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward), Principles of Environmental Science (William P. Cunningham; Mary Ann Cunningham), Campbell Biology (Jane B. Reece; Lisa A. Urry; Michael L. Cain; Steven A. Wasserman; Peter V. Minorsky), Topics for Exam 4 - Summary General Chemistry, Laboratory techniques option one report (1) Nicholas Mc Quagge, and magnesium sulfate, also known as Epsom salt. Answer: _____ b) Calculate the number of moles of water in the hydrate sample that were driven off by heating? Be sure your beaker and glass rod does not have any crack, and that that they are clean and dry. Such compounds ar, compounds that have a specific amount of wat, writing the formula of a hydrate, a dot connects t, that of water and is viewed as an addition sign i, lose all or part of their water of hydration when e, this dehydration is accompanied by a colour chang, Give Me Liberty! 1.) In this lab, we learned how to apply stoichiometry in a new way to determine a formula of a hydrate. Students dehydrate copper (II) sulfate pentahydrate, crucible or evaporation dish and use their data to determine the % composition and the number of, molecules per formula unit of copper (II) sulfate. and from their collected data, calculate their, for several reasons. From the masses of the water and anhydrous solid and the molar mass of the anhydrous solid (the formula of the anhydrous solid will be provided), the number of moles of . Balance Then, they heat the, experimentally. Calculate the percent error of your experiment. The following data were obtained when a sample of barium chloride hydrate was analyzed: Mass of empty test tube 18.42 g. Mass of test tube and hydrate (before heating) 20.75 g A hydrate is a chemical compound, generally ionic, that has weakly bonded to it a specific number of water molecules per formula unit. : an American History (Eric Foner), Biological Science (Freeman Scott; Quillin Kim; Allison Lizabeth), Psychology (David G. Myers; C. Nathan DeWall), Educational Research: Competencies for Analysis and Applications (Gay L. R.; Mills Geoffrey E.; Airasian Peter W.), Forecasting, Time Series, and Regression (Richard T. O'Connell; Anne B. Koehler), Brunner and Suddarth's Textbook of Medical-Surgical Nursing (Janice L. Hinkle; Kerry H. Cheever), The Methodology of the Social Sciences (Max Weber), Business Law: Text and Cases (Kenneth W. Clarkson; Roger LeRoy Miller; Frank B. By multiplying the mass of the anhydrate, which is magnesium sulfate in the experiment, with its molar mass, the number of moles present at the end can be determined. Lorem ipsum dolor sit amet, conse iscing elit. the aluminum dish and Epsom salt to Data Table 1. If you found this article useful, please . Thus, the ratio between water and magnesium sulfate will be close to being 7:1. BOLD and Change the color of your answer to RED so the teacher could easily find them! This water can be driven off by heat to form the anhydrous (dehydrated) ionic compound, magnesium sulfate. Spatula Data can be collected and most of it analyzed, single 45-50 class period. If too much heat is applied, the anhydrous copper (II) sulfate (CuSO4), which has a grayish white color, decomposition starts at 250 degrees, while complete decomposition occurs around 600 degrees. Furthermore, this lab illustrated a new term for the group - hydrate. From the data the students can determine the experimental percentage of, composition and empirical formulas. 7H 2 O) is a heptahydrate of magnesium sulfate: within one mole of magnesium sulfate heptahydrate are seven moles of water. This product contains 13 pages of chemistry multiple choice WITH ANSWERS on calculating the mass percent of an element, calculating the percent composition of a compound, determining a compounds empirical formula from percent data or mass data, determining the molecular formula of a compound and solving for the number of water molecules in a hydrate. An insufficient amount of time for waiting until all water of the hydrate evaporated. Lab 09 - Percent of Water in a Hydrate Pre-Lab Questions Date: Name: - Section: Instructor: - Read the following laboratory experiment and answer the questions below. The reaction for the decomposition is as follows: In this part of the lab you will repeat the same procedure performed for the salt of known formula with a salt for which you do not know the hydrate formula. Setup the ring stand with iron ring and ring. The identity of the mysterious substance was magnesium sulfate. The mass of water evaporated is obtained by subtracting the mass of the anhydrous solid from . 1. Why purchase my version of this. The hydrate was heated until all the water evaporated, and the mass of the remining anhydrous salt was measured. Then, the experimental ratio of water to magnesium sulfate being 6.63 to 1 with about 6% error strongly supports our hypothesis to a deeper level. To calculate the molar mass, we added up each element's atomic mass for each part of the substance. Nearly half of the mass of the hydrate is composed of water molecules within the . As 6.63:1 is relatively close to 7:1, the expected ratio for this substance, we can thus conclude that the unknown hydrate is magnesium sulfate heptahydrate, MgSO47H2O. Become Premium to read the whole document. Students will be given the formula of the anhydrous form, but the number of, are unknown. when we heat blue CuSO5HO, what happens? 120.3 g percentage of water in hydrate (from teacher) 51.2 % Processing Your Lab Data. ? What can transform a hydrate into an anhydrous salt? The change from hydrate to anhydrous salt is accompanied by a change in color: For example, Glucose is C6H12O6; it's empirical formula is CH2O. Second, it will also determine the molar ration of water to inorganic salt in Epsom salt. Stop heating when the salt has lost all traces of blue color. A student performed the experiment correctly and the initial massing correctly, but forgot to mass the crucible cover after heating. Second, the results are great! The mass of water evaporated is obtained by subtracting the mass of the anhydrous solid from the mass of the original hydrate ( 2.12.3 ): mH 2O = mHydrate mAnhydrous Solid. A hydrate is a compound that is chemically combined with water molecules. The change, mass observed allows them to calculate the amount of, COMPOSITION EMPIRICAL FORMULA Multiple Choice Grade 11 Chemistry (13 PG), This product contains 13 pages of chemistry multiple choice WITH ANSWERS on calculating the mass, data or mass data, determining the molecular formula of, 12 font, times new roman, without text boxes and condensed into the least amount of space possible.
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