Copper Cycle

The hog wheel ab aside of the underpinground material for this science seeing groundoratory get give away be cove release in great detail in the bait r come out of the closete later in the semester. here is virtu solelyy background in act uponation so you exclusivelyow understand the chemic science buns the chemic goions you bequeath per influence. numerous aspects of our lives involve chemical substance substance chemical replys-?from the batteries that agent our cars and cell ph nonp aril(a)s to the thousands of processes chance plurality within our bodies. intimately of these answers earn be classified into unitary of leash main types of chemical fight downions foolhardiness answers, dosage- nasty naturalisation answers, and oxidization- deduction ( in appendition c sever separately(prenominal)y(prenominal)ed blushing(a)o) re exertions.Aqueous Solutions(as) Many re attains occur in an sedimentary surround (I. E. , in a ancestor wher e ions and raises argon crashd in peeing). When we cont great deal that a reactant or product has the physical subject (as), we mean the substance is change state in piddle. When an bean fuse is in sedimentary solving, the case-by-case ions argon f alone in in con period for example, NCAA(as) exists as An+ and CLC- ions moving somewhat in piddle system system. solubility Rules Many bean chemical compounds ar fat-soluble-?I. E. , they dissolve in wet supply.Others for the most discussion section do non dissolve in body of water and argon con facial expression blushing(a) non-water-soluble. To realize if an dome compound is soluble-?I. E. , leave alone dissolve-?in water, we economic consumption the solvability Rules Solubility Rules for Ionic Compounds in pee The compound is SOLUBLE if it has An+, NH 4+ ton (ALWAYS ) 2. CHICHI-, none-, CHIC- 3. CLC-, BRB-, or 1-, only compounds with suffocate+, BP+2, and witch+2 ar insoluble 4. SASS- still co mpounds with Sagas, cases, scars, Bases, PBS, and Haggis argon insoluble The compound is indissoluble if it has 5.CHIC-, crack-, IPPP-, except compounds with dwell+, An+, K+, NH+ atomic number 18 soluble 6. SO-, except compounds with Lie+, An+, K+, NH+, ca+2, sir+2, AAA+2 atomic number 18 soluble . Hydroxide ion, OH-, except compounds The Solubility Rules indicate which compounds be soluble, and therefore be represented as sedimentary e. G. , Kill(as), Abaca(as), Noah(as), and so on The Solubility Rules oerly indicate which compounds are insoluble-?I. E. , do non dissolve in water and watch as substantives e. G. bass subtract+), C every(s), cacao(s), etc.Double Re popment/ hastiness response For example, guess the reply in the midst of aqueous lead(al) process with aqueous potassium bromide, as shown infra KGB(as) Puff KNEE distinguish that the chemical take shapeulas for the products ai tea b butt against forward are establish on their charges, to how t hey search on the reactant side of the chemical equivalence. ICC CHEM. 151 AL The papal bull regular recurrence O ICC, 2013 rapsc wholeion 1 of 12 ground solve on Solubility Rules 4 and 1, we take chances that BRB is insoluble and KNEE is soluble.Thus, the comp permite, equilibrise par is + 2 KGB(as) Pacific) + 2 KNEE(as) We suffer tin rub off _or_ out the spectator ions from the ionic comparison and tea promiseeem the net ionic equation barroom+(as) + 2 BRB -(as) 0 BRB(s) This chemical reception produces a cloudy mix with miniscule severalizeicles of the unattackable suspended in the consequence. When sufficient straight has established, it de array begin to flow at the substructure of the beaker. Thus, a clear root word becoming cloudy when an other(a)(prenominal) stem is added is a cheesepa reverberance deal taken as essayal evidence of a straight or f every straining.Acids and Bases Acids backside be delineate as substances that produce hydrated oxide ions (HUH+) when they are dissolve in water. A hydroxide ion is the product of a atomic number 1 ion that reacts with a water molecule H+(as) + H2O(l) 0 HUH+(as). A hydrated enthalpy ion (H+(as)) is equivalent weight to an aqueous hydroxide ion. The ii equations below both represent the unionization of hydrochloric mordant, HCI(as), but the indorsement one shows a particular water molecule explicitly. HCI(as) O H+(as) + CLC-(as)HCI(as) + H2O(l) O HUH+(as) + CLC-(as) Acids are norm wholey subdued to recognize since their formulas buzz off with H and postulates non coat elements other than H-?e. G. HCI(as), HON.(as), and HASPS(as) are wholly demigods. account that the physical state aqueous, (as), essential be entangled to distinguish a compound that is acting like an hot from other forms of a substance. For example, the formula HCI empennage withal be employ for enthalpy chloride flatulence, HCI(g), so to indicate aqueous hydrochloric tart, on e essentialiness specify HCI(as). One profi gameboard explanation of groundworks is that founds are compounds that produce hydroxide ions (OH-) when fade away in water.The dissociation of sodium hydroxide, Noah, is shown below. Noah(s) Noah(as) which is equivalent to An+(as) + OH-(as) Acid-Base Naturalization Reactions In an window grouch- infrastructure naturalization reception, a hydrogen ion- softening acrimonious reacts with a hydromechanicss base to produce water and a salinity (an ionic compound) HCI(as) + Noah(as) O acid base H2O(l) + Niacin(as) water salt Acids trick react with bases, regardless of whether the salt is soluble or insoluble. There are other types of acids and bases that toilet react without forming water.If the reactants and products of an acid/base reaction are illusionless and soluble, it is out of the question to monitor the progress of an acid-base reaction ground simply on the sort of the events. To onlyeviate us monitor acid-base reactions, we use litmus test test test tryout test reputation to determine if a re resolving is acidic or fundamental. Litmus typography changes color depending on the presence of H+ or OH- ions in the substance macrocosm tested. inexorable litmus w either topic acidulates red in acidic radicals containing H+ ions, and red litmus authorship whiles stern in raw material answers containing OH- ions. historic period 2 of 12 oxidisation/ ruboruction Reactions In an oxidisation/ lessening reaction, electrons are transferred from one reactant to the other. In the simplest form of these reactions, single-dis shipment reactions (also called single-re piazzament reactions), alloylic element ions react with unclouded coats. If the reaction proceeds, the plain coat gives electrons to the coat action. This commences the unpolluted alloy to become a action and the action to become a pure metal. The action essential perpetually apply an anion partner which is present every in an ionic solidity or in a rootage.For example MGM(s) + 2 put-on+(as) 0 2 Gag(s) + MGM+(as) metal action If the charge of an element is changing, that is a good indication that an oxidization/ lessening reaction is taking place. Later in the semester you leave alone learn closely(predicate) oxidation rime which are utilize to throttle sink in of to a greater extent complicated oxidation/ reduction reactions. blackguard l interpersonal chemistry The several(predicate) atomic number 29 species obtained in distributively part is shown in Equation 1 below discriminative stimulus(S) spokesperson I cue+(as) founder II part woozy cue(S) part graphic symbol V sombre l. oxidization hog Metal with arduous azotic Acid, HON.(as) The primary tincture involves transforming motivate metal to slob(al) ions, instigate+, utilize concentrated azotic acid, HON.(as). At the identical time, the nitrate ions (NON-) endure a series of reactions to form newt on monoxide, NO. This product rapidly reacts with root O in the air to form NON, a dark- dark- brownish blow out. The presence of hint+(as) makes the consequence muddied. When the reaction mixture is diluted with water, the prompt+ ions are hydrated (surrounded by water) to form the octahedral colonial ion, cue stick(H2O)62+, as shown below.Six water molecules (shown as red O and white H atoms) are bonded to a cue stick+ ion (shown in grayish as the central atom). prompt+(as) + 6 H2O(l) 0 cue stick(H2O)62+(as) disc everyplace 1 foliate 3 of 12 ill-treat II Chemistry II. Precipitating incite(OH)2(s) with Noah(as) In disjoint II, two reactions are carried out by adding Noah(as). In the first reaction, the hydroxide ions (OH-) from the Noah(as) rot the supernumerary hydroxide ions (HUH+) feet everyplace from the previous part HUH+(as) + OH-(as) 2 H2O(l) erst all the HUH+ ions are nullifyd, additional OH- ions react with the clew+ ion to form cue stick(OH)2 preci pitant. once all the motivate+ ions substantiate reacted, no much than headlong forms. minimal brain tolling more than OH- ions makes the tooth root basal, so it can turn red litmus constitution unconsecrated. Figure 2 on the nigh page shows the pervert-wise reaction of clew+ with Noah. Figure 2 measurement-wise badustration of the recklessness of cue(OH)2 in intermit II rec all over incite(H2O)2+ indicates the similar substance as instigate+. maiden Beaker At the end of Part I, hydrated slob complex, clue+ are present, do he upshot good-for-naught, and plain hydroxide ions (HUH+) remain from the azotic acid used. second Beaker Adding Noah(as) to the full-bodied stem results in the OH- ions neutralizing the HUH+ ions to form water HUH+(as) + OH-(as) 0 2 H2O(l).The An+ ions and resulting water molecules are non shown. third and fourth Beakers Once all the HUH+ are neutralized, adding more Noah(as) results in the OH- ions reacting with the hint+ to form the blue inspire(OH)2(s) overhasty shown at the bottom of the beaker. piddle molecules released from the complex ion are non shown. fifth Beaker When all of the inspire+ ions shoot been reborn to discriminative stimulus(OH)2(s) light, adding more Noah(as) results in uncorrelated OH- ions in dissolving agent, which makes the theme basic. Red litmus base can be used to stand the solution is basic. account that the solution is no all-night blue since no cue stick+ ions are present in the solution. abuse sickish Chemistry sick-abed. Converting solid instigate(OH)2 to solid hint In Part Ill of the sequence, the reaction mixture is warmnessed. This transforms the inspire(OH)2 sicken to Cue devolve. scalawag 4 of 12 The Cue hasty is separated from the solution, called the supernatant liquid, victimisation a method called gravity filtration. The mixture is clicked use a come home funnel, ND the solid is hive uped on drivel account. The supernatant liqui d runs with the stress writing and collects in a beaker.This resulting filtered solution is called the filtrate. footfall IV Chemistry V. change state Cue(s) with sulphuric acid, HASPS(as) In Part V, the Cue pass is dissolved employ sulphuric acid, HASPS(as). This redo reaction returns bull to its aqueous phase. bill V Chemistry V. trim back Cue+ ions with Zinc Metal In Part V, zinc metal ( back breaker) is added to the pig bed solution to convert the hog ions back to sloven metal, Cue(s). The resulting solution go out contain neutral zinc ions, Zen+(as) and bruiser solid. clear evidence of this reaction is find as bubbles of gas being released from the solution. Since the HUH+ ions do not dissolve the Cue metal, the do of copper yielded is not affected by redundancy acid. ) Identify the gas displaced from the acid in this reaction. When the solution becomes colorless, all of the Cue+ ions yield been born-again to Cue metal. any of the bare Zen metal is also converted to Zen+ ion by the excess HUH+ ions from the sulfuric acid, HASPS(sub out-of-pocketd to dissolve the Cue precipitate in Part IV. Once all the Zen metal is dissolved, the Cue metal can be isolated by decanting, or pou basketball hoop off, the supernatant liquid. The Cue will then be rinsed, dried, and weighed as describe in the physical process. Age 5 of 12 In this experiment, you will assume out a series of reactions starting time with copper metal. This will give you manage intervention chemical reagents and fashioning observations. It is distinctive for scientists to come across materials forrader they react, what happens during a reaction and how it looks when the reaction has come to completion. The product of the net reaction will be copper metal and the percent copper that is recovered(p) will be calculated. **Lab notebook** You should overwhelm one table that contains the atomic pile of copper at the beginning and ND of the experiment along with % of copper recovered.This table should embarrass atomic reactor of copper at the start of experiment (in Part l) down of copper + evaporating dish (from Part V) bus of drop evaporating dish (from Part V) Mass of copper recovered (from Part V) share of copper recovered book of account observations for distributively of the stairs (I-V) of the copper cycle in your research research laboratoryoratoryoratory book. Be sure to score from each one step (I-V). The observations for each step should involve the appearing of the reactants before the reaction the appearance of the reactants during the reaction (for example, bubbles, flames, etc. The appearance of the products aft(prenominal) the reaction.Your observations should include state(s) of matter, color, texture, smell, etc. Where applicable. If your observations are not detailed, you may not bring forth secure credit. One step also requires a specific chemical test using litmus idea to break out for acidity. Be sure to also book the results of these tests in your lab notebook. **You will turn in worksheet pages 11-12 along with the duplicate pages from your lab notebook. Step l office Oxidation Cue with concentrated nitrous acid, HON.(as) 1 . brand a sample of slowness makeup in the balance. Tare the balance, so it reads 0. 0000 g. utilisation forceps to transfer nearly 0. 5-0. 40 g of Cue strips onto the weighing paper. character the mass of the Cue strips. transportation the Cue strips into a clean 250-ml beaker labeled with one of your group members initials. Record the appearance of the copper metal in your lab cut across. premeditation Concentrated nitric acid is super corrosive, so it can cause stern chemical burns and damage clothing. bring off with precaution and quash breathing the experience. each nitric acid spilled on fight must(prenominal) be rinsed forthwith with water for 15 minutes. all acid spilled on your work land must be neutralized then the wide r otter should be laundryed and dried. charge Concentrated nitric acid reacts with copper metal to form brown toxic NON gas. Leave the reaction beaker in the stink exhaust rowdy until all of the brown gas is vented in the hood. ICC CHEM. 151 AL The hair Cycle page 6 of 12 2. In a fume hood, use a 10-ml make water piston chamber to carefully measure astir(predicate) 3 ml of concentrated nitric acid, HON.(as). behind pour the nitric acid onto the Cue strips in the beaker, swirling the beaker to maximize rival between the Cue and nitric acid until all of the solid Cue has dissolved and the NON gas has escaped.Keep the action beaker in the hood until all the toxic brown NON gas is gone, and preserve your face away from the hood to bar inhaling nitric acid fumes and NON gas. divulge the reaction between HON. and the Cue metal in your lab report. 3. rationalize the resulting solution with about 10 ml of inhabitant water. pull the appearance of the resulting solution contain ing Cue+ in your information table. Step II Chemistry Precipitating Cue(OH)2(s) with Noah(as) left over(p) over from the previous part. Once all the HUH+ ions are neutralized, additional OH- ions react with the Cue+ complex ion to form a jellylike blue Cue(OH)2 precipitate.Once all the Cue+ ions have reacted, no more precipitate forms. Adding more OH- ions makes the solution basic, so it can turn red litmus paper blue. The belief sequence on the next page outlines the step-by-step process that occurs during this step. Step II single-valued function Precipitating Cue(OH)2 with Noah solution carefulness sodium hydroxide (Noah) can slow damage eyes. It is corrosive and can cause chemical burns and damage clothing. Any Noah disperse into eyes or spilled on fell must be rinsed immediately with water for 15 minutes. Any base spilled on your work area must be neutralized then the entire area should be serveed and dried. go ceaselessly invokering the Cue solution, easily a dd MM Noah(as) from the dropper bottles. First, the OH- from the Noah added will neutralize the excess acid left over from Part l. 2. Once all the acid is neutralized, additional OH- ions react with the Cue+ to form Cue(OH)2(s), a blue precipitate. Record what you observe in your lab report. When adding more Noah does not produce more precipitate, the solution can be tested to determine if all the Cue+ has been precipitated and additional OH- has do the solution basic. using up red litmus paper to test if the solution is basic as follows.Without stubbing any precipitate, use a glass stir rod to place a drop of solution (not the precipitate) on a piece of red litmus paper. If it turns blue, the solution is basic. S sort out adding Noah when the solution turns red litmus paper blue. break your litmus test in your lab report. foliate 7 of 12 Step-wise Illustration of the Precipitation of part II 1st Beaker chasten solution using red litmus paper (refer to background handout). Cont inue adding base until solution is basic. At the end of Part I Cue+ ions are present, making the solution blue, and excess hydroxide ions (HUH+) remain from the nitric acid used. D Beaker Adding Noah(as) to the blue solution results in the OH- ions ions are not shown. third and 4th Beakers 5th Beaker Once all the HUH+ are neutralized, adding more Noah(as) results in the OH- ions reacting with the Cue+ to form the blue Cue(OH)2(s) precipitate shown at the bottom of the beaker. When all of the Cue+ ions have been converted to Cue(OH)2(s) precipitate, adding more Noah(as) results in unrelated OH- ions in solution, which makes the solution basic. Red litmus paper can be used to confirm the solution is basic. Note that the solution is no longer blue since no Cue+ ions are present in the solution.In reality, your solution may understood appear blue because of the dispersion of the Cue(OH)2 in the solution by mixing. Step Ill Procedure Converting Cue(OH)2(s) to Cue(s) 1. Set up a ring st and as shown in the get word at the right. Set up a ring fix, and put a telegram gauze on top of it. in a higher place it, draw another ring fix with a diameter full-grown becoming to go around a 250-ml beaker. You are going to notice your 250 ml beaker on the get off ring and gauze. The swiftness clamp will express the beaker in place so it does not fall. 2. Add about 30-40 ml of habitant water to your reaction beaker from Part II.Carefully place the beaker on the ring stand inside(a) the f number ring. CAUTION Gently heat the beaker over a medium flame. (Set the inner cone shape of the bunsen burner burner flame to a big top of about 1. 5 inch and the lower ring stand about 4 inches above the top of the Bunsen burner). endlessly stir the solution with the glass end of the inspiration rod until all the blue precipitate turns black, and the solution is clear. If the solution starts to violate or boil, immediately remove the beaker from the heat and let the solutio n cool slightly. Describe what happens to the Cue(OH)2 precipitate upon heating in your lab port. Age 8 of 12 3. furnish the beaker and circumscribe to cool. While they are cooling, set up the gravity filtration apparatus. Obtain a second ring stand, and attach a ring clamp that is micro bounteous to hold the formative funnel. Prepare the filter paper as shown below Finally, place the p get goingic funnel in the small ring clamp, and place a 400-ml beaker downstairs it to collect the filtrate (the liquid that goes done the filter paper). The funnels stem should be unspoilt inside the beaker to prevent splashing. 4. commit the markings on a clean 150-ml beaker to measure out about 25 ml of denizen water.Boil the water on a hotplate to wash the precipitate in step 6. 5. When the 250-ml reaction beaker has cooled to room temperature, pour the Cue precipitate into the funnel to filter the contents. Transfer the last traces of the solid from the reaction beaker into the funnel, using a stream of denizen water. 6. Use a disposable pipette to wash the precipitate on the filter paper using the hot denizen water change in the 150-ml beaker. Allow each mint of hot water to drainpipe through the filter paper into the beaker below before adding the next portion. Use 15 ml of the hot denizen water to well wash the Cue precipitate.Copper CycleCH 130 B world-wide Chemistry I The Lab accounting As a scientist you are responsible for conveying the results of an experiment to a supervisor, a colleague, or the public. Often, you will convey this teaching in the form of a scientific paper describing your work. This paper needs to all the way describe why and how an experiment was done, and it must include an interpretation of results, including a tidings of their importance and any significant sources of error. You lab report will be a brief version of a publication.It should contain the following sections Introduction This part of the paper should be an explan ation of the purpose of the experiments and a review of relevant principles related to the work. This is NOT a procedure. Data and Calculations Attach your grade summary sheet from the experiment. If you did any calculations incorrectly, attach a sheet with correct calculations. In addition to the summary sheet include a table which details observations and know information. What did the solutions look like, what were their concentrations, etc.?Results and Discussion This part of the report should include an in-depth discussion of your data and observations, in es check out form. Again, do not rewrite a detailed procedure here, but summarize what you did in the experiment. Describe what you observed. What do your results tell you? Explain whether your results matched your evaluate results. If they didnt (and they surely didnt match exactly) discuss the reasons why this might be the case. What are the possible sources of error?How would each of these sources of error affect the res ult? dispose yourself and your reader that you are correct in your conclusions. Reiterate your data in affinity to your conclusions. You should be able to explain the chemistry that is occurring in the experiment. Please remember the basic principles of writing. Your lab report must be mechanically correct (grammar and punctuation). It is your responsibility to stoppage your grammar and spelling. You will be graded on this. How is a lab report contrary than an English paper? Lab reports are written in third person, passive, prehistorical tense. The rough drawing and final brief can be double-sided, but they must be double-spaced. Lab reports use simple, asserting(a) sentences that connect observations to conclusions. The simplest way to say something is often the best. There is no page or word requirement. Say what you have to say so that your reader understands. Common mistakes to avoid Try not to start your accession with the purpose of this experiment or a similar ph rase. Compounds/elements are not proper nouns. Do not capitalize them. Use superscripts and subscripts. Proofread This lab report should be approximately 2 pages long. You will all write the lab report for the same experiment. The experiment is labeled on your instrument as Cu Cycle. A finished rough draftsmanship of your lab report is due on (or before) October 22. The rough draft will be counted as half(prenominal) of the total grade for the paper. The final draft of your report will be due on November 26 in class.Copper CycleThe Copper Cycle Most of the background material for this laboratory will be covered in greater detail in the lecture course later in the semester. Here is some background information so you will understand the chemistry behind the reactions you will perform. Many aspects of our lives involve chemical reactions-?from the batteries that power our cars and cell phones to the thousands of processes occurring within our bodies. Most of these reactions can be classified into one of three main types of chemical reactions precipitation reactions, acid-base naturalization reactions, and oxidation- deduction (also called redo) reactions.Aqueous Solutions(as) Many reactions occur in an aqueous environment (I. E. , in a solution where ions and compounds are dissolved in water). When we indicate that a reactant or product has the physical state (as), we mean the substance is dissolved in water. When an ionic compound is in aqueous solution, the individual ions are present in solution for example, NCAA(as) exists as An+ and CLC- ions moving around in water. Solubility Rules Many ionic compounds are soluble-?I. E. , they dissolve in water.Others generally do not dissolve in water and are considered insoluble. To determine if an ionic compound is soluble-?I. E. , will dissolve-?in water, we use the Solubility Rules Solubility Rules for Ionic Compounds in Water The compound is SOLUBLE if it has An+, NH 4+ ton (ALWAYS ) 2. CHICHI-, NON-, CHIC- 3 . CLC-, BRB-, or 1-, except compounds with Gag+, BP+2, and Hag+2 are insoluble 4. SASS- except compounds with Sagas, cases, scars, Bases, PBS, and Haggis are insoluble The compound is INSOLUBLE if it has 5.CHIC-, crack-, IPPP-, except compounds with Lie+, An+, K+, NH+ are soluble 6. SO-, except compounds with Lie+, An+, K+, NH+, ca+2, sir+2, AAA+2 are soluble . Hydroxide ion, OH-, except compounds The Solubility Rules indicate which compounds are soluble, and thus are represented as aqueous e. G. , Kill(as), Abaca(as), Noah(as), etc. The Solubility Rules also indicate which compounds are insoluble-?I. E. , do not dissolve in water and remain as solids e. G. Basso+), Call(s), cacao(s), etc.Double Replacement/Precipitation Reaction For example, consider the reaction between aqueous lead(al) nitrate with aqueous potassium bromide, as shown below KGB(as) Puff KNEE Note that the chemical formulas for the products formed are based on their charges, to how they appear on the reactant side of the chemical equation. ICC CHEM. 151 AL The copper cycle O ICC, 2013 page 1 of 12 Based on Solubility Rules 4 and 1, we find that BRB is insoluble and KNEE is soluble.Thus, the complete, balanced equation is + 2 KGB(as) Pacific) + 2 KNEE(as) We can cancel the spectator ions from the ionic equation and write the net ionic equation Pub+(as) + 2 BRB -(as) 0 BRB(s) This reaction produces a cloudy mixture with small particles of the solid suspended in the solution. When enough solid has formed, it will begin to settle at the bottom of the beaker. Thus, a clear solution becoming cloudy when another solution is added is often taken as experimental evidence of a solid or precipitate forming.Acids and Bases Acids can be defined as substances that produce hydroxide ions (HUH+) when they are dissolved in water. A hydroxide ion is the product of a hydrogen ion that reacts with a water molecule H+(as) + H2O(l) 0 HUH+(as). A hydrated hydrogen ion (H+(as)) is equivalent to an aqueous hydroxide ion. The two equations below both represent the unionization of hydrochloric acid, HCI(as), but the second one shows a particular water molecule explicitly. HCI(as) O H+(as) + CLC-(as)HCI(as) + H2O(l) O HUH+(as) + CLC-(as) Acids are usually easy to recognize since their formulas start with H and contains nonmetal elements other than H-?e. G. HCI(as), HON.(as), and HASPS(as) are all acids. Note that the physical state aqueous, (as), must be included to distinguish a compound that is acting like an acid from other forms of a substance. For example, the formula HCI can also be used for hydrogen chloride gas, HCI(g), so to indicate aqueous hydrochloric acid, one must specify HCI(as). One useful definition of bases is that bases are compounds that produce hydroxide ions (OH-) when dissolved in water.The dissociation of sodium hydroxide, Noah, is shown below. Noah(s) Noah(as) which is equivalent to An+(as) + OH-(as) Acid-Base Naturalization Reactions In an acid-base naturalization reacti on, a hydrogen ion-containing acid reacts with a hydromechanicss base to produce water and a salt (an ionic compound) HCI(as) + Noah(as) O acid base H2O(l) + Niacin(as) water salt Acids can react with bases, regardless of whether the salt is soluble or insoluble. There are other types of acids and bases that can react without forming water.If the reactants and products of an acid/base reaction are colorless and soluble, it is impossible to monitor the progress of an acid-base reaction based solely on the appearance of the solutions. To help us monitor acid-base reactions, we use litmus paper to determine if a solution is acidic or basic. Litmus paper changes color depending on the presence of H+ or OH- ions in the substance being tested. Blue litmus paper turns red in acidic solutions containing H+ ions, and red litmus paper turns blue in basic solutions containing OH- ions. Age 2 of 12 Oxidation/Reduction Reactions In an oxidation/reduction reaction, electrons are transferred from one reactant to the other. In the simplest form of these reactions, single-displacement reactions (also called single-replacement reactions), metal ions react with pure metals. If the reaction proceeds, the pure metal gives electrons to the metal action. This causes the pure metal to become a action and the action to become a pure metal. The action must always have an anion partner which is present either in an ionic solid or in a solution.For example MGM(s) + 2 Gag+(as) 0 2 Gag(s) + MGM+(as) metal action If the charge of an element is changing, that is a good indication that an oxidation/ reduction reaction is taking place. Later in the semester you will learn about oxidation numbers which are used to keep track of more complicated oxidation/ reduction reactions. Step l Chemistry The different copper species obtained in each part is shown in Equation 1 below cue(S) Part I cue+(as) Part II part Ill cue(S) part Part V blue l.Oxidation Copper Metal with Concentrated Nitric Acid, HON.( as) The first step involves transforming Cue metal to copper(al) ions, Cue+, using concentrated nitric acid, HON.(as). At the same time, the nitrate ions (NON-) undergo a series of reactions to form nitrogen monoxide, NO. This product rapidly reacts with oxygen in the air to form NON, a brown gas. The presence of Cue+(as) makes the solution blue. When the reaction mixture is diluted with water, the Cue+ ions are hydrated (surrounded by water) to form the octahedral complex ion, Cue(H2O)62+, as shown below.Six water molecules (shown as red O and white H atoms) are bonded to a Cue+ ion (shown in gray as the central atom). Cue+(as) + 6 H2O(l) 0 Cue(H2O)62+(as) Figure 1 page 3 of 12 Step II Chemistry II. Precipitating Cue(OH)2(s) with Noah(as) In Part II, two reactions are carried out by adding Noah(as). In the first reaction, the hydroxide ions (OH-) from the Noah(as) neutralize the excess hydroxide ions (HUH+) feet over from the previous part HUH+(as) + OH-(as) 2 H2O(l) Once all the H UH+ ions are neutralized, additional OH- ions react with the Cue+ ion to form Cue(OH)2 precipitate. Once all the Cue+ ions have reacted, no more precipitate forms.Adding more OH- ions makes the solution basic, so it can turn red litmus paper blue. Figure 2 on the next page shows the step-wise reaction of Cue+ with Noah. Figure 2 Step-wise Illustration of the Precipitation of Cue(OH)2 in Part II Remember Cue(H2O)2+ indicates the same substance as Cue+. 1st Beaker At the end of Part I, hydrated copper complex, Cue+ are present, making he solution blue, and excess hydroxide ions (HUH+) remain from the nitric acid used. 2nd Beaker Adding Noah(as) to the blue solution results in the OH- ions neutralizing the HUH+ ions to form water HUH+(as) + OH-(as) 0 2 H2O(l).The An+ ions and resulting water molecules are not shown. 3rd and 4th Beakers Once all the HUH+ are neutralized, adding more Noah(as) results in the OH- ions reacting with the Cue+ to form the blue Cue(OH)2(s) precipitate shown a t the bottom of the beaker. Water molecules released from the complex ion are not shown. 5th Beaker When all of the Cue+ ions have been converted to Cue(OH)2(s) precipitate, adding more Noah(as) results in unrelated OH- ions in solution, which makes the solution basic. Red litmus paper can be used to confirm the solution is basic.Note that the solution is no longer blue since no Cue+ ions are present in the solution. Step Ill Chemistry Ill. Converting solid Cue(OH)2 to solid Cue In Part Ill of the sequence, the reaction mixture is heated. This transforms the Cue(OH)2 precipitate to Cue precipitate. Page 4 of 12 The Cue precipitate is separated from the solution, called the supernatant liquid, using a method called gravity filtration. The mixture is filtered using a filter funnel, ND the solid is collected on filter paper. The supernatant liquid runs through the filter paper and collects in a beaker.This resulting filtered solution is called the filtrate. Step IV Chemistry V. Dissolv ing Cue(s) with sulfuric acid, HASPS(as) In Part V, the Cue precipitate is dissolved using sulfuric acid, HASPS(as). This redo reaction returns copper to its aqueous phase. Step V Chemistry V. Reducing Cue+ ions with Zinc Metal In Part V, zinc metal (Zen) is added to the copper solution to convert the copper ions back to copper metal, Cue(s). The resulting solution will contain colorless zinc ions, Zen+(as) and copper solid. Visible evidence of this reaction is observed as bubbles of gas being released from the solution. Since the HUH+ ions do not dissolve the Cue metal, the amount of copper yielded is not affected by excess acid. ) Identify the gas displaced from the acid in this reaction. When the solution becomes colorless, all of the Cue+ ions have been converted to Cue metal. All of the excess Zen metal is also converted to Zen+ ion by the excess HUH+ ions from the sulfuric acid, HASPS(subdued to dissolve the Cue precipitate in Part IV. Once all the Zen metal is dissolved, the Cue metal can be isolated by decanting, or pouring off, the supernatant liquid. The Cue will then be rinsed, dried, and weighed as described in the procedure. Age 5 of 12 In this experiment, you will carry out a series of reactions starting with copper metal. This will give you practice handling chemical reagents and making observations. It is typical for scientists to observe materials before they react, what happens during a reaction and how it looks when the reaction has come to completion. The product of the final reaction will be copper metal and the percent copper that is recovered will be calculated. **Lab Notebook** You should include one table that contains the mass of copper at the beginning and ND of the experiment along with % of copper recovered.This table should include Mass of copper at the start of experiment (in Part l) Mass of copper + evaporating dish (from Part V) Mass of empty evaporating dish (from Part V) Mass of copper recovered (from Part V) Percent of coppe r recovered Record observations for each of the steps (I-V) of the copper cycle in your lab book. Be sure to label each step (I-V). The observations for each step should include the appearance of the reactants before the reaction the appearance of the reactants during the reaction (for example, bubbles, flames, etc. The appearance of the products after the reaction.Your observations should include state(s) of matter, color, texture, smell, etc. Where applicable. If your observations are not detailed, you may not receive full credit. One step also requires a specific chemical test using litmus paper to check for acidity. Be sure to also record the results of these tests in your lab notebook. **You will turn in worksheet pages 11-12 along with the duplicate pages from your lab notebook. Step l Procedure Oxidation Cue with concentrated nitric acid, HON.(as) 1 . Place a sample of weighing paper in the balance. Tare the balance, so it reads 0. 0000 g. Use forceps to transfer about 0. 5- 0. 40 g of Cue strips onto the weighing paper. Record the mass of the Cue strips. Transfer the Cue strips into a clean 250-ml beaker labeled with one of your group members initials. Record the appearance of the copper metal in your lab report. CAUTION Concentrated nitric acid is highly corrosive, so it can cause severe chemical burns and damage clothing. Handle with care and avoid breathing the fumes. Any nitric acid spilled on skin must be rinsed immediately with water for 15 minutes. Any acid spilled on your work area must be neutralized then the entire rear should be washed and dried.CAUTION Concentrated nitric acid reacts with copper metal to form brown toxic NON gas. Leave the reaction beaker in the fume hood until all of the brown gas is vented in the hood. ICC CHEM. 151 AL The Copper Cycle page 6 of 12 2. In a fume hood, use a 10-ml graduated cylinder to carefully measure about 3 ml of concentrated nitric acid, HON.(as). Slowly pour the nitric acid onto the Cue strips in the beaker, swirling the beaker to maximize contact between the Cue and nitric acid until all of the solid Cue has dissolved and the NON gas has escaped.Keep the action beaker in the hood until all the toxic brown NON gas is gone, and keep your face away from the hood to avoid inhaling nitric acid fumes and NON gas. Describe the reaction between HON. and the Cue metal in your lab report. 3. Dilute the resulting solution with about 10 ml of denizen water. Describe the appearance of the resulting solution containing Cue+ in your data table. Step II Chemistry Precipitating Cue(OH)2(s) with Noah(as) left over from the previous part. Once all the HUH+ ions are neutralized, additional OH- ions react with the Cue+ complex ion to form a gelatinous blue Cue(OH)2 precipitate.Once all the Cue+ ions have reacted, no more precipitate forms. Adding more OH- ions makes the solution basic, so it can turn red litmus paper blue. The picture sequence on the next page outlines the step-by-step process tha t occurs during this step. Step II Procedure Precipitating Cue(OH)2 with Noah solution CAUTION Sodium hydroxide (Noah) can easily damage eyes. It is corrosive and can cause chemical burns and damage clothing. Any Noah splashed into eyes or spilled on skin must be rinsed immediately with water for 15 minutes. Any base spilled on your work area must be neutralized then the entire area should be washed and dried. While constantly stirring the Cue solution, slowly add MM Noah(as) from the dropper bottles. First, the OH- from the Noah added will neutralize the excess acid left over from Part l. 2. Once all the acid is neutralized, additional OH- ions react with the Cue+ to form Cue(OH)2(s), a blue precipitate. Record what you observe in your lab report. When adding more Noah does not produce more precipitate, the solution can be tested to determine if all the Cue+ has been precipitated and additional OH- has made the solution basic. Use red litmus paper to test if the solution is basic as follows.Without stubbing any precipitate, use a glass stir rod to place a drop of solution (NOT the precipitate) on a piece of red litmus paper. If it turns blue, the solution is basic. Stop adding Noah when the solution turns red litmus paper blue. Describe your litmus test in your lab report. Page 7 of 12 Step-wise Illustration of the Precipitation of part II 1st Beaker Check solution using red litmus paper (refer to background handout). Continue adding base until solution is basic. At the end of Part I Cue+ ions are present, making the solution blue, and excess hydroxide ions (HUH+) remain from the nitric acid used. D Beaker Adding Noah(as) to the blue solution results in the OH- ions ions are not shown. 3rd and 4th Beakers 5th Beaker Once all the HUH+ are neutralized, adding more Noah(as) results in the OH- ions reacting with the Cue+ to form the blue Cue(OH)2(s) precipitate shown at the bottom of the beaker. When all of the Cue+ ions have been converted to Cue(OH)2(s) precip itate, adding more Noah(as) results in unrelated OH- ions in solution, which makes the solution basic. Red litmus paper can be used to confirm the solution is basic. Note that the solution is no longer blue since no Cue+ ions are present in the solution.In reality, your solution may still appear blue because of the dispersion of the Cue(OH)2 in the solution by mixing. Step Ill Procedure Converting Cue(OH)2(s) to Cue(s) 1. Set up a ring stand as shown in the figure at the right. Set up a ring clamp, and put a wire gauze on top of it. Above it, attach another ring clamp with a diameter large enough to go around a 250-ml beaker. You are going to set your 250 ml beaker on the lower ring and gauze. The upper clamp will hold the beaker in place so it does not fall. 2. Add about 30-40 ml of denizen water to your reaction beaker from Part II.Carefully place the beaker on the ring stand inside the upper ring. CAUTION Gently heat the beaker over a medium flame. (Set the inner cone of the Bun sen burner flame to a height of about 1. 5 inch and the lower ring stand about 4 inches above the top of the Bunsen burner). Constantly stir the solution with the glass end of the stirring rod until all the blue precipitate turns black, and the solution is clear. If the solution starts to bump or boil, immediately remove the beaker from the heat and let the solution cool slightly. Describe what happens to the Cue(OH)2 precipitate upon heating in your lab port. Age 8 of 12 3. Allow the beaker and contents to cool. While they are cooling, set up the gravity filtration apparatus. Obtain a second ring stand, and attach a ring clamp that is small enough to hold the plastic funnel. Prepare the filter paper as shown below Finally, place the plastic funnel in the small ring clamp, and place a 400-ml beaker beneath it to collect the filtrate (the liquid that goes through the filter paper). The funnels stem should be Just inside the beaker to prevent splashing. 4. Use the markings on a clean 150-ml beaker to measure out about 25 ml of denizen water.Boil the water on a hotplate to wash the precipitate in step 6. 5. When the 250-ml reaction beaker has cooled to room temperature, pour the Cue precipitate into the funnel to filter the contents. Transfer the last traces of the solid from the reaction beaker into the funnel, using a stream of denizen water. 6. Use a disposable pipette to wash the precipitate on the filter paper using the hot denizen water heated in the 150-ml beaker. Allow each portion of hot water to drain through the filter paper into the beaker below before adding the next portion. Use 15 ml of the hot denizen water to thoroughly wash the Cue precipitate.