4 Emperical Formula

4 Emperical Formula - a?” A Name PEG??? Section...

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Unformatted text preview: a?” A Name PEG??? Section EXPERIMENT 4 : EMPIRICAL FORMULA 0U PRE-LABORATORY QUESTIONS 2 The following preparatory questions should be answered before coming to lab. They 3 E are intended to introduce you to several ideas that are important to aspects of the E ; experiment. You must turn in your work to your instructor before you will be : 2 allowed to begin the experiment. I 1. A compound is made up of38.67 % C, 16.22 % H and 45.11 % N. Calculate its empirical formula. 8 Ema. a 7 ¥ 4 33""! Q. , M T- ..mi A“. ‘4‘: 9. EZ‘QKGJQ w a; ,/-\ m” 22% 5. 3mm *r..’/ . m _ CO . z) 46. x *3. is} i “lxmim 273 w M 0629,14. (MN m remit 1. An inorganic salt is composed of 7.73 g Ca, 6.17 g 0 and 0.389 g H. What is the 3., empirical formula of the compound? - 9 40.0784éQq "' :3; Q’C‘HQZ’ lg Qfifigqflg W (13%}? - Z r‘ e 7 a 1 9‘3??? / gt/g. my“; 3 / \ g VI! W i \ 0.10;?) 3. The percent composition of a substance that is used as an engine coolant is found to be 38.70 % carbon, 9.74 % hydrogen and 51.55 % oxygen. i! 7 I; L/ Cheml414—AcademicYear2010/2011 4—1 . . g1 I. .r g a) What is the empirical formula of the compound? 3370032" V‘ Emmi = 3.22??- W “g i V \ cl 034.05%.‘95 m p xq‘eg Mg ma afifigg is. 3mm 1 3‘22 tasqaaqgc 53% b) Its molar mass is 62.07 g/mol. What is the molecular formula of the compound? Q: z-zamm -: meme ‘9‘ 14$ "; tpsg%ig :2 3} 0245A G 7‘ 2:: gaieggaz‘o (02.01 lvacg‘i A“ :2: Z §%,§§%§mo‘t m is m It} aware“; " QZQC6LZ‘ NI Chem14l4—Academic Year 2010/2011 4 2 Name 30» Section ©0\ RESULTS Mass of crucible and cover 1__ Mass of magnesium (a o . a Mass of crucible, cover and product First weighing 22. ‘35 .55 Second weighing 2235'? ’ié Third weighing SIGN-OUT: All equipment is put away, and the student be h is clean and dry. TA figs Date <34 Mg CALCULATIONS Moles of magnesmm @\23;5%?% am“ J 2 “WM 1.; 0.81:3 ea. , _ fifisfi-ia V5323 Mass of product _' ZZgg—ig -' 22.54%}; 3'; Q\3\Z§ Mass of oxygen r OfialZghfififiéfi :. O‘Q‘Igflé Q Moles ofoxygen CLO-M) a} & grim; ‘: O, 005 Mole ratio of magnesium to oxygen 0| Q g {3 Z , M Empirical formula of magnesium oxide 0 ‘V ma nesium in ma nesium oxide 1 0 g g 53.7339 75.96/46 «.3 a; o . . . A) oxygen 1n magnes1um ox1de Q's—7% 5 ‘00 :- Zfi‘fflg [a 6 612.2 ,I‘~\ Chem1414—Academic Year 2010/2011 POST LABORATORY QUESTIONS 1. When the magnesium is not allowed sufficient oxygen, some magnesium nitride, Mg3N2, forms. If the Mg3N2 is not decomposed, will the reported Mg to 0 mole ration be high or low? Explain your answer. I"? “€342; {fir-‘55:??fi? WQOABEQ N193 3N; are) flag; Q as 0g. mg} ./’How would not allowing the crucible to cool to room temperature before weighing the product affect the outcome of the experiment? Would the Mg to 0 mole ratio be higher or lower than expected? r a 7/ Higher madam there woséd be lose: white H—é; has: / JET/RA. Scott told her TA that the molecular formula of magnesium oxide is the same as a the empirical formula. Is she correct? Show how you arrived at your answer. 4- ‘xi 1 ./ a Noi “We eamgsgefim‘z Q’mmeta tfigfifi was}. “the matewimr "iatroulct mga {/A/ How would spilling some of the product from the crucible affect the outcome of the , experiment? Would the Mg to 0 mole ratio be higher or lower than expected? f» It would be lower became ‘gw m 5’33‘31‘3 Mg from 4W: fitment fi"3§;§g%t 5. Chemical analysis of a sample that is used for dry cleaning gave the following results: 2.251 g C, 0.284 g H and 9.966 g Cl. What is the empirical formula of the compound? ‘= V in i ZxZ$1gC A .2: “weir; u. i t r 018% “ *M‘W = daggqgi 3: “mm figimg\C/\ Chem14l4-Academic Year 2010/2011 4—8 ...
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This note was uploaded on 11/28/2011 for the course CHEM 1414 taught by Professor Slaughter during the Spring '07 term at Oklahoma State.

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4 Emperical Formula - a?” A Name PEG??? Section...

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