Chem-Ex. 6 - Name fil L19 Cu'l(lg Section 0.7 “I 5...

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Unformatted text preview: Name. fil L19 Cu'l (lg Section: 0.7 “I 5 Date: [0'19 “0-5 ’ 3’7 4C EXPERIMENT /470 /§/ 1. Flame Tests for Zn)“, Cu“, and A +. Do flame tests on solutions which contain these ions. Report your results in the following table. Solution Tested Color Time Zinger 87in /MD i 12.105 g QQPQ CA} 09:4)? Cmgcfl (i 5 Shier M t-LOJC 5‘) 6 £50” '4; Q 6.1 Does it appear that Zn2+, Cu“, or Ag+ is detectable by flame test analysis? Tell why or why not. .ch is t1 pi 24%:(5 MWVLWUR 1945th Sings Calor- 2. B/L Acidity of Zni OHgifiz”, Cu(OH2)52+, and Ag(0H2)2+. Use indicators to assess the pH (to one S ..F ) of solutions of Zn(OHZ)62+ and Ag(OHz)2+. 2Use indicator paper m 1— 2 cm strip) to assess the pH (one S. F. ) of a solution of Cu(OH )62 (Since Cu(OI-I2 )62+ is colored, in—solution indicator testing is not reliable for pH estimation.) Report your results in the following table. NOTE: Use indicator paper for pH assessment only if the solution to be tested is deeply colored. Solution Tested Ion Tested Results (Indicator(s)lColor(s)lpH) 2,4; We 2,1on 5” 9‘ new we '7 Wage (if? (229% OILOIiJi' C—U(0H 3?— M4 AdflES/ji . Qi U“ Minsk @6141»: Mgr/M 5mg]; ——7 «1:313 PM; i) Q 6. 2 For each of the above write the equation for the principal equilibrium which shows why [H3 0 ] IS different from [H3 ] for deionized water. Milk +11. we“ 5(0H‘iwzoi CULOHZX + (12,9 Glows (014% ”4703K @(bflflfaio ~7 4? (ergo/4m 1 i470” 6—7 Formation and Properties of Hydrated Zine Hydroxide. Q6.3 Based on solution—pH's of hydrated metal ions, you should not expect V Zn(OH2)4(OH)2 to be amphoteric. Why? 2m (OHMOH): \5 \thj 6&1de M ‘JM‘Q €01“) 3; gclfm a7 wax/rt (3656“? M H20 Use NaOH solution to prepare a small quantity of Zn(OH2)4(OH)2(s)t T hen, by further testing with NaOH solution, determine the approximate minimum [HO’] necessary to readily dissolve Zn(OH2)4(OH)2(s). Be careful in your observations to distinguish between dispersion and dissolution. Q 6.4 Describe experiments and results for the above. W NR 0‘4 W25 1“;er “5‘14 @ '21-“ Nltgrztle A 1 LI ll) Mi ML 95 L [4 WM 6 Z (GPA (0 25‘ 14 we J'GéalvéSI/L Mu: am New was “M Q 6.5 Write the equation for the reaction in which Zn(OH2)4(OH)2 was formed by treatment with H07. 2m (0H7)? 4’ 20H” ——> Znfioflaqéml we? Q 6.6 Write the equation for the reaction in which Zn(OI-IZ)4(OH)2 was dissolved by treatment with HO‘. 2m (Gas)! (614); + ZOH' .9 ”'ZHCOHZSZCOHlf—k +ZHZG Formation and Properties of Hydrated Copper Hydroxide. Q 6.7 Should Cu(OH2)4(OH)2 be more readily amphoteric or less readily amphoteric than Zn(OH2)4(Ol-I)2 ‘3 Why? [65,194qu {L 23 a-norlx 4% f ago Lawaflc) «lo ZACOHL debt As above in section 3. for Zn(OH2)4(OH)2 (s), prepare some Cu(OH2)4(OH)2 (s) and then determine the minimum [HO"] necessary to produce apparent dissolving of Cu(OH2)4(OH)2 (s). (Hint: Try 6 M NaOH.) , Q 6.8 Describe experiments and results for the above including a color description/ distinction for Cu(OH2)62+, Cu(OH2)4(OH)2 . and Cu(OH2)2(OH)42’. .1 . z m u. or, 1113 C0 F Chime?) WNW-05‘ {>1 [If ./:r [EjUi’VW Hue fiwj W? L/J‘U A 4th , . (J - m Wt. bum a} 2m MW Mazda M W WI?! LI/ /I‘330/ Further Investigations on Zn(OH2)2(OH)4Z- and Cu(OH2)2(OH)42F. Freshly prepare an individual solution of each of these ions. Carefully heat each solution to boiling and examine for precipitate formation. Treat the hot solution of Zn(0H2)2(OH)42_ with 1 — 2 drops of 0.5 M ZnSO4 if precipitate formation did not occur. Similarly, treat the hot solution of Cu(OH2)2(OH)42’ with 1 — 2 drops of 0.5 M CuSO 4 if precipitate formation did not occur. Repeat as necessary until precipitate formation occurs in each solutiOn. Retain precipitates for subsequent investigations. Q 6.10 Describe observations and results for each of these experiments. [No (for Quote) Wit!“ Lmicj CDKOHZXZCOIUQZK Qty} when W CUSO”! WMS UJJQJ A blaC’K/ bp‘m IVF’L ”film/Irv Aflzeaf‘éoi I N9 Wu «Wei palm, Why-j anOHbg<0HlP but Wm M @501 1915 Milo) a Mule Wt QMW/ wash-JV .. Q 6.11 Write the equation for each reaction which has just occurred. (Neglect the e {feet / . of added Zn(OHZ)62+ or Cu(OH2)62+ in these equations.) PC) 3. "iii Q L G 2“ (Cl/12% (OH “r?" $ 246%!» 4 2H0” i ZHzO' CJ(0H231(0H)WL~ z‘: c0053 4. 2 W ”we 6—9 Defend. (Hint: Consider color changes.) W .U Ea-Wx wml \la prlum 62mm Ma helm—Ll“ Galore/M ~ 71% 2‘4 3”" MMP NJ W Cay/SSA.» Puma! 5M’ Q 6.13 Write the equation for the reaction in which CuO can be dissolved in (i) a solution rich in H30+. )4 ._ . ’ '2. L40 + $HVQ .4 1%“ —~?..QL/CH29)¢ < (ii) a solution rich in HO‘. 0.40 + who + we!“ ~> Maggi (OW Devise and perform experiments for dissolving ZII(OH)2(S) in both acidic and basic solution. Do the same for CuO(s). Q 6.14 Describe experiments and results for the above. 77¢ om won 0M) (9M ML! 196% dimmed “33 (41 W ZHCOH>1CQQ I in cm H61 Assam) as CUO Jpn/w OM Urea“ )1) M Q 6.15 Which method for dissolving Zn(OH)2(s) is more practical? How about Cu0(s)? Why? N30” {[6 Wfi {NIH/Ho]? / 6-10 Formation and Pro erties of Silver Oxide. Repeat experiments performed as in sections 3. — 5. above to prepare some Ag20(s) and to test the soiubilityiof this material in both acidic and basic solution. Q6.16 Descéribe experiments and mitt/s foghéigwe. ’M [Uh 6W 4b _ 03 )M rig/w); ea Wag/Mt e g; M, ,L W/ gigs/()7 I " - . U, . ,s [‘ Aldcdycoicsr V pm ya we MIRA dezfflntig elgfm 33/ NEH Q 6.17 Write the e nations for any reactions which just occurred. Z/Lf) (OH 2 L + 2440w ‘3’ [@310 JSHzG s so w <7 we was we» Q 6.18 In these e§periments (above), what evidence was obtained to indicate that brown— black Ag20(s) is more stable than white, gelatinous Ag(OH2)(OH)(s)? Explain as necessary. flee brawn AQLO :5 mi ver/ easily (JiSSO/Ufldi ROMS W A (OH; 660 gyms easy awe/ V19 (wisely daésgeee) 33/ Md Q 6.19 Which substance seems easier to form, CuO or Agp? Why? ‘ ASLC) because. 1L (i083 Mi’ Veg/vine W [WM z) Investi ations Involvin Zn2+ and NH . Treat a solution which contains Zn(OH2)62+ with 3 M NH3 added dropwise. Stir after adding each drop of 3 M NH3 and stop after some but n_01; all of the precipitate, Zn(OH2)4(OH)2(S), has dissolved. Assess [H07 ] in this solution with indigo carmine (HIC) indicator. (Note: In order to be usable in a reliable fashion, the HIC indicator solution on the reagent shelf must be deep blue.) Q 6.20 Describe observations and results for the above, including a reference to drops of 3 M NH3 used, indicator color (in the test solution), and [H0“ ]. - " ' fi v6 4’54 Pp} .4 Leah bavl’ Maw?) 05} 3m. NH; Hdtsgix Oil” i4» 2);]; carmrmc wfi Maid W £91101”!!! fir % \{inw p [2b. (#2 MM“ @325 anger WM) 6-11 Repeat this entire investigation using 1 — 2 M NaOH solution in place of 3 M NH3. Q 6.21 Describe observations and results for the above including a reference to drops of v NaOH solution used, indicator color, and [H02 ]. _ - < NM {fir 20:4er we” iv w W W W; W CW‘PWW ditssolu - . m as We W Me a were (M e ”i Q 6.22 Based on the results of your work in section 7., does Zn(OH2)4(OH)2(s) dissolve in 3 M NH3 to give the zincate ion? Defend. (Hint: Think carefully about the {H01 which resulted in each investigation and note that zincate ion must have been produced in the equilibrium established using NaOH solution.) Wm“ M Mi; / W emwfe ism ‘W Md pregfiwt. {LL pH 5 new Aral, 8”? W wt“ Mia ’ZLW\i-€ “[004 «in MAD” wldkm /' OK Investigations Involving Cu2+ and NH3. Treat a solution which contains Cu(OI-12)62+ with 3 M NH3 added dropwise with stirring until precipitation occurs. Save results. Q 6.23 Describe observations and results for the above. 3-i- Jni‘f £00k— 3 (9ng {IO Mué Ct SifééCrttibe apt/MM: {Mi-3 a (cal/H glue Cloudy 601W“. Q 6.24 Write the equation for the reaction which has just occurred. as our film. -7 Cu 3. it) M) (A Wild $09909 + 2W W1 Continue to treat the precipitate-containing mixture with more drops of 3 M NH3. Count drops as you add and stir until the mixture becomes totally clear. 6—12 Q 6.25 Note the total number of drops of 3 M NH3 added and describe any observed changes. aboui‘ [{6} drops Jrurmwi 4%»: with” Widely )fierilt ‘olUQJ Q 6.26 Your work in section 8. should indicate that a new, previously uninvestigated substance of Cu2+ has been formed. Tell why this is true based on results obtained in sections 4. El 8. A Lelerenl» color blue Q 6.27 Write the equation for the reaction which occurred above on treatment of the precipitate with excess 3 M NH3. Investigations Involving Ag’r and NH3. Prepare some A go and also prepare some AgCl. Treat each substance individually with 6 M NH3 added dropwise in excess with stirring. Save. Q 6.28 Report your results for the above. Based on your results from treatment with 6 M NHB, which substance, AgZO or AgCl, appears to be more stable? aWG dmps OF A310 A30 :3 mare '3ka about 5C: $0395 a? 61;le Q 6.29 If the above solutions are treated with HONO2 solution, what will happen? Make a prediction and defend it. 00320 will )erm [9&me 0H will bml/ko’PF 6—13 Q 6.30 By experiment, test the prediction you made in response to Q 6.29 and report your observations and results. (9ng firms no 444 cm?— Jiwci W $30 Wha- EM} 84% 0K3? 0 was Clmr“ Q 6.31 Which substance appears t- 3.: stronger bonds Ag ‘2 Circle your for each case. (i) NO; 0 @‘7 (ii) H0‘ or (iii) NH3 0 Q 6.32 What should happen if a sample of AgZO is shaken with excess 1 M NaCl for a long time? Why? OLSC.\ Sinevib germ }-\' koé 8W MS will/’5 @i’ OK 6-14 Name: Section: Date: PROBLEMS FOR ASSIGNMENT 6 P 6.1 Write the equation for the principal reaction which occurs when: (i) AgZO is dissolved in NH3 solution. @330 + 4MH3 + HLO ‘7 Q ILQEMHS]; + 20H“ (ii) AgCl is dissolved in NH3 solution. dam + o7WH3 a a3 Mug] 3*“ + cr (iii) The resulting solution in (i) is acidified with lLIONO2 solution. an (we); +<3H‘ + 3%,0’27 Ac; +a NM +01 ”20 (iv) The resulting solution in (ii) is acidified with HONO2 solution. asW‘QSHI“ + ZHbo’ —-> Age! + gamut 4 2,420 P 6.2 What evidence was obtained by experiment in Assignment 6 to support the conclusion that an electrostatic, ion~dipole model premised on NGS, cannot be 2+ ? used to explain the chemistry of Zn(OH2)6 41446315 a E/L— ““5 P 6.4 Based on work in Assignment 6, tell how to prepare pure CuC12 - ZHZO from CuSO4 - SHZO without loss of 012+. [Note: Gentle evaporation of a water solution of Cu(OH2)62+ and Cl‘ produces crystals of CuCl2 - 2H20.] i) dissolve W Cusott ism/o @ :0 H06 2- ii) Jerewi Milo COM Naou it, Meg CU(HLO)L(EM>L, e Mir )0 4&ng COG . weak .1146 Oil/17L +£69.91 WiH Mai 6-15 P 6.5 Tell how to prepare pure zinc chloride and pure silver chloride from a water solution which contains Zn(OHZ)62+, Ag(OH2)2+, and SO? as the principal ionic solutes. _/ Tread W filolrcim WI‘HK Z-(p Wk Nam-l {.0 Cake Zn (H2951 (0H),; ‘ aw) A3510. Walt-e. 6WD mask (Mac 44% W4. Wis with Hat is comer} W @310 i6 QSCI i Wafl‘ , C)!“ are] Level” ":24 (HzOLCOHJf l0 661+ 1.10 " Separate His and wash M1”) HCJ P 6.6 Consider: Ag(NH3)2+(aq) Cl‘(aq) fi AgCl(s) + 2 NHafaq). Calculate K for this equil' rium and, based on the value which you obtain, comment on NH3 versus Cl’ toward making stronger bonds with Ag+. Show work. M , [NHsja {mm X kp(A3[“%]) X M (436:) “ D l _o «a .... = r. 13on? umao' -~=— 35vLO 350 > It Gage *0 “fl” P 6.7 Tell how to test a soluti n for Zn(OH2)62+ if the solution is guaranteed to contain A1(0H2)63+. (Assume at no other metal ions are present in the solution.) 6-16 ...
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