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40; so 5 2014 Dgl/yaHpc Tang cirofng huOig thu hoc tap hoa hpc cua hpc sinh lofp 10 thong qua thirc hanh thf nghiem ThS LE THI THUY DUNG Khoa Khoa hpc Ty nhien, TrUdng Dai hpe Hong Dtle I VAI TRO CUA[.]
40; so 5-2014 Dgl/yaHpc Tang cirofng huOig thu hoc tap hoa hpc cua hpc sinh lofp 10 thong qua thirc hanh thf nghiem ThS LE THI THUY DUNG Khoa Khoa hpc Ty nhien, TrUdng Dai hpe Hong Dtle I VAI TRO CUA THl/CC HANH THI NGHIEM TRONG GIANG D^Y VA HQC TiOiP H A HQC phin hda vd cd idp 10, nham giQp cho viSc sQ dung TN dpy hpc hda hpc duyc thudng xuyen hdn, Phan Hda hpc vd cd Idp 10 tap trung vao chUdng la chUdng 5: Nhdm halogen va ehudng 6: Nhdm oxi Hda hpe la mdn hpc thyc nghiSm Iran ed s3 nam vQng ly thuyet Yeu td dac trUng chfnh la kim chi nam cho cdng tac, II MOT SO THf NGHIEM HOA HOC TRONG NOI giang dpy va hpc tap mdn tida hpc Do dd, phUdng phap nhpn ^DUNG HOA VO C a L ( P thUe diing dan v l hda hpcia phki dya trln nhQng kel qua Thi nghiem 1: Dieu che d o nghien cQu thuc nghiem ket hdp ehat ehe vdi eac If thuylt cd a) Muc dth thf nghiem ban ve hda hpe NhU vay, sif dyng thf nghiem (TN) giang ' GiQp HS nam duyc nguyfen tac chung ciia dieu che dpy la mpt phan khdng the thieu dpy hpc hda hpe, Nd phdng thf nghiem giup hpe sinh chuyen iQ tu ey the sang tu IrQu tuyng va - Cho HS quan sat mau sac eiia elo nguyc Ipi Khi quan sal TN, HS se lam quen vdi cac chat hda - Dung dilu ehe' dUde de lien hanh cac thf nghiem sau hpe va irye lilp nam bat eac tfnh chit li hda hpc ciia chiing b) Cd sd ^ thuydt Trong dpy hyc hda hoe trudng thdng ed dpng TN Nguyen tac chung cua dilu c h i phdng Ihf nghierrr gdm: TN bieu diln cDa giao vien {GV) va TN eiia hoe sinh la cho axit HCI dpc lac dyng vdi chat oxi hda mpnh nhU: MnO^, (HS) TN bieu dien la ed sd de ey the hda nhQng khai niem ve KMnO^, KCIO3,,', cha't va phan ung hda hpc, GV la ngUdi IhUe hien cac thao tae, MnOg + HCI -> MnCI^ + H^O + Cl^ (dun nong) dieu khien cac qua trinh bien doi ciia chat, H5 theo ddi va gial KMnO, + 16 HCI ^ KCI + MnCI^ + H^O + Clj, thfeh eae hien luyng xay lien quan den ndi dung bai hyc, TN KCIO3 + HCI ^ KCl + H p + Cl^ ciia HS la HS tryc liep nhpn dung cy va ty thyc hien cac TN, c) Di^ng cu, hda chit dilu khiln cac qua trinh biln ddi cua chit dudi sy hudng d i n - Dyng cy: Binh cau dung tieh 250 mi, binh cau ed khda eiia G V Thye hanh thi nghiem giang dpy va hpc lap hda (hope phlu brdm), ong d i n cong, binh thuy tinh, nQl cao hpc cd Uu diem noi bat sau: su, bong, gia dd, den cdn, - Giup GV giang dpy v l tfnh cha't If hda hyc c6a eac chat ro - Hda chal: MnO^, hoac KivlnO^, KClOg, CaOCIg, dung dich rang va trpn y vi Idi ndi rat IrQu tuyng cdn TN Sii ey the, HS tiep HCI dae {d=1,19g/ml), dung djch NaCl bao hda, dung djch thu kiln thQc chfnh xae, vQng chae, hieu bai va nhd lau vi cd an H^SO, dac (98%), dung dich NaOH dac, tUdng sau sae vdi hinh anh, Tpn mat nhin thiy nhQng hien d) Ky thuit tidn hanh tuyng hda hpc xay ra, HS se lin tUdng vao kien IhUc da hpc, - Lap dyng cy nhu hinh ve - TN la cau ndi giQa li' thuyet vdi thyc t l , Nhilu TN ra't gan gui vdi ddi sdng, vdi cac quy trinh edng nghe, giiip HS van dyng eae dieu da hpe vap thyc t l cudc sdng - TN GV bilu diln se od cac thao tac chfnh xae, miu myc va an loan TN HS thyc hian se giiip HS ren luyen kT nang thyc hanh, phat then nang lyc trf tuS, phat huy tfnh sang lao, Dac bidt, thye hanh thf nghiem se giup HS them yeu thich mdn hpe, iQ dd cd ddng lyc va hQng thQ de hpe tpp tot, Trong thyc te giang dpy d trudng thdng hien nay, TN cdn it dUde sir dyng bai giang, ke ca cac TN da dUde hudng d i n Irong sach giao khoa, neu cd sir dyng thi ehl la eac thi nghiem ddn gian, chii yeu la minh hpa cho cac kien thQe da Hinh Dieu che oxi biet Bai vill dUa each tien hanh mot sd TN giing d^y 41 Dglfy^HpCsos - Cho khoing - g MnO^ vao binh c^u (cho s i n trudc lap dyng cy) Rot 30 - 50 ml dung dich HCI vao p h l u brom, Cho 50 ml dung dich NaCI vao binh 1, 50 ml dung djch H^SG, dae vao binh 2, |gy bdng tam dung djch NaOH dpc - Md khda cho dung djch HCI ehay xudng tQ IQ, dun nong nhp, thu d o thoat e) Hidn tugng vi giii thfeh Thu duyc khd ed mau vang luc f) Thi nghiem thay the - Khi khdng ed axil HCI dpe thi cd the Ihay bang axit HjSO^ dac eho lac dung vdi hdn hdp MnO^ va NaCI khan (tlia ve khdilUdng 2:1), - N l u dieu c h i mdt luyng nhd elo, ed the dOng dng nghiSm cd nhanh thay cho binh eau, dng nho gipt thay cho p h l u dUng HCI d5c, kh( d o duyc thu tryc l i l p hope thu qua nudc vao dng nghipm, g) An toin thi nghiem Khi dpc, vpy tien hanh thf nghiem phai dee khau trang, gang tay, mac ao blue, tien hanh lu hd't, ehuan bi s i n binh dUng NaOH loang de lopi bd khf elo khdng dung den, Tuyet ddi khdng nhim vdi thf nghiem KMnO, tac dyng vdi H^SO, dac, Thf nghiem 2: Clo tac dyng vdi kim lopi Natri va Sal a) Muc dich Ihf nghiem ChQng minh linh oxi hda mpnh ciia clo b) Cd sd 1:^ thuyet Na + Cl^ ^ NaCI Fe + Cl^ -> FeCI^ e) Dung cu, hoa chit - Dyng cy: mudi ddng, den con, dao eat, m^u than go, t^m kfnh dpy (hope bia cactong) - Hda cha't: binh khf elo mdi dieu ehe, m^u natri, - syi day phanh xe dap, d) Kp thuat tien hanh - Cat mpt mau natri to bang hat dau xanh, cat bd het idp oxit xung quanh va dung giay Ipc tham khd dau Lay mudi ddng spch lau khd, cam xuyen qua tam bia, khdng d l mudi dong eham vao day binh (khoang 2/3 binh), sau dd cho mau Na vao, dun ndng tren ngpn IQa den edn den Na ndng ehay hoan loan eo mau sang dng anh rdi dua nhanh vao binh clo, - L l y syi day sat nhd hope day phanh xe dap dai khoang 20 - 30 em, udn htnh Id xo cd gan mau than gd e l m mpt dau day sat xuyen qua t i m bia, khdng chpm day binh Dot ndng mdt dau day rdi dUa nhanh vao binh clo da cd mdt ft nUdc Nam cliiy Irong t^ ngO" lnB sing Hinh Scncf^fS^' cnSy Hon Hinh Clo tdc dyng Na vd Fe e) Hien tUdng va giai thfdi - Natri nong chay chay sang vdi ngpn IQa mau vang, cd khdi trang va mdl ft khdi nau bay Khdi Irang la NaCI sinh Khdi nau Ihoai mudi dong phan iTng vdi tpo ddng (II) dorua, hope mau natri chua lau spch dau nen ankan phan iihg vdi - Day sat nung dd chay sang ^ong clo, Ida nhieu nhiat Thu duyc dung dich mau vang nau cua FeCI^ f) Thf nghiem thay 6ie Cd the dQng day ddng, milng nhdm thay cho Na va day sat g) An toin thf nghiem - Khdng nen eat mau Na qua to, can xQ If Na sau tiln hanh thi nghiem, - Khdng dot ehay syi day sat, khdng dung maufrianqua Idn de lam moi, Cpo spch syi day sat Chf cho nude vao binh bat dau lien hanh hd ndng day sal {vi tan nUdc) Thf nghiem 3: Clo am ed tac dyng tay mau a) Muc dich thf nghiem Chifng minh tinh oxi hda mpnh cua axU hipodord b) Cd sd ly'thuyet Khi lan vao nUdc, mdt phsh tac dyng cham vdi nUde theo phan Lfng thuan nghich: Cl^ + H ^ ' ^ H C I + HCIO Axit HCIO cd tfnh oxi hda rat mpnh, nd pha hiiy eac ehat mau, vi t h i am cd tac dyng l l y mau c) Dung cu, hda diat Gidng vdi thi nghiem 1: Dieu che elo, thu khf elo vao binh da cd slui mdt ft nudc cat va bang giay mau (hope eanh hoa ed mau) d) / KjMnO^ + MnO^ + 0^ (dun ndng) H^Og ^ H^O + 0^ {dun ndng, xue lac MnO^} c) Dung cu, hda chat - Dyng cy: 6ng nghiem, lp thijy tinh mieng rdng, dng din khf cong, nut cao su, chau Ihiiy linh, gia sat den eon - Hda chat: KCIO^, MnO^ linh the d) Ky thuat tien hinh - Lap dyng ey nhu hinh ve - Trdn gam KCIO3 da nghien nhd vdi khoang 1,25 gam MnOj (If le 4:1) rdi cho hdn hdp vao mdl dng nghiem khd Cham den con, hd ndng diu hda chat dng nghifem sau dd dun tap trung tpi did cd chQa nhilu hda chat Thu oxi thoat bang each day nudc 42 ^ E _/NCAy NAY Hinh Bieu che oxi e) Hipn tuyng va giai thieh Thu duyc khf oxi thoat bang each day nUdc f) Thf nghilm thay the - Cd t h i thay hdn hyp (KCIO3, MnO^) bang khoang gam KMnO^ hope dung djch H^O^ bao hda + MnO^, dd dung djch HjOj nim tren phlu brom, edn MnO^ cd s i n dng nghiem, - Thu oxi bang each day nude hope day khdng khf g) An loan thf nghiem - Sau lap dyng cy, thQ dd kfn ciia thiet bj bang each lay mpt It nudc cho vao dng din khf, Sau niil vao dng nghiem neu myc nUdc dng d i n khf thap hdn mieng dng dan khf Ihi thiet bj da kfn, - KhI lap dng nghiem da chQa hda chat len gia sal can lUu y: mi^ng dng nghiem phai hdi chuc xudng d l phdng hdn hyp cha't r i n I m , dun hdi nudc bay len se khdng ehay nguyc ipi, lam v8 dng nghiem ' - KCIOgIa mptjchat gay no nen khdng nghiln nhieu mpt luc, khdng nghien lanvdi bat ki chat nao khae Lp dyng KCiO^ khdng duye de hd nQl, nhat la de cpnh P, C, S, - De tranh hien tQyng eac hpt tinh the KMnO^ bi khf 0x1 day vao dng dan khf, nen d l mdt Idp bdng gan mieng dng nghiem, g i n dng dan khf, - Khdng thu khf tir nhQng bpt khf dau tiSn vl edn l l n khf nild khdng khf - NgUng Ihu khf thao ong d i n khf trudc tat den cdn, Thr nghipm 5: Oxi tac dyng vdi kim lopi hoac phi kim a) Myc dfch thf nghiem Nghifen eQu kha nang phan Qng ciia O^vdi Fe, Na, S b) Cd sd ly thuyet Fe + O^ - ^ hdn hyp oxit vao dieu kien phan Ung Na + Oj - ^ Hap + Oj ^ SOg c) Dyng ey, hda chat - Dyng cy; Lp IhCiy tinh mieng rdng, den cdn, mudi, bia eaetong, dua IhCiy tinh - Hda chat: Binh khf oxi, day phanh xe dpp da cudn Id xo ed gan go nho, nUde cat, cat, Natri, bpt luu huynh d) Ky thupt tiln hanh - TUdng ty nhU thf nghiem 2: Clo tac dyng vdi kim lopi natri va sat, thay binh khf clo bang binh 0x1, - Ddi vdi luu hu^nh, dot ndng mdt d i u diia thuy tinh rdi cho eham vao lUdng nhd S, bdi S ndng chay bam vao dau dua, dUa vao binh oxi e) Hien tuyng va giai thieh - Natri ehay sang vdi ngpn iCfa mau vang, - Sat chay sang, nhilu hpt nhd sang ban nhU phao hoa, xua't hien hat mau den dUdl day binh la oxit sat, - LUu hL)i/nh chay manh liet oxi, ngon iQa mau xanh lam, f) Thf nghiem thay I h l Cd the Ihay day sat bang day ddng, miing magie g) An loan thf nghlem - Trong binh oxi cho s i n nudc hope cat de tranh vd binh - Khf SOjddc nSn khdng d l thoat ngoai mdi trudng Khdng de dua thuy linh ndng chpm vao luyng Idn S, va chpfn vao binh, Tdm l§i, TN hda hyc cd vai trd rit quan tryng dpy hpc • hda hpc Viec td chQc thyc hanh eae thf nghiem giang dpy hda hpe phd thdng la rat can thiet can dQdc quan lam dQng mQe PhO hdp vdi chien luyc phat triln giao dye va dao tao cLia nudc ta la: giang dpy phai Uu tien ap dyng linh hopt, IhUdng xuyen cac phUdng phap dpy hpc tfch eye, ed linh tryc quan eao, sQ dyng cac phUdng lien, thiet bj da dpng, sinh dpng, coi thUe hanh, thyc nghiem Tai lieu tham khSo Nguyin CUOng Phuong phap giang dpy va thf nghiem Hoa hpa NXB Giao due, H,2001, Nguyin CUOng, Nguyin Mpnh Dung, Giao Irinh PhUdng phap dpy hpchoahpc, Tap III, NXB DHSP, H.2007 Nguyin Thj Kim Anh Lupn an ten sTGiao dye hpc, Renluy?nkT nang dpy hpe Iheo hudng lang cUdng nSng lyc ly hpc, ty nghiSn cQU ciia sinh vien khoa hoa hpc nganh sU phpm d cac trudng dpi hpcTnrdng DHSP HaNpi,H, 2012 Trln Qudc Die, Hudng din Ihyc hanh Hda 10, NXB Giao dye H 2007 Vu TTii Loan Hda hpc dpi eUdng NXB DHSP H 2004 6.LBXuanTrpng,TifNgpcAnh,LeMauQuyln,PhanQuangTha SGK Hdahpc 10 Nang cao NXB Giao due H.2006 Tirkhda: Hda hpc vdcd {inorganic chemistry), Thfnghipm (experiments), IhUc hkih (practice), oxi (oxygen), (chlorine) J\ Hinii OXI lac d^ng v&i Na Hinh Oxi tdc dung Fe Htnh Oxi lAc dung vdi Luu hupnh ... mpt mau natri to bang hat dau xanh, cat bd het idp oxit xung quanh va dung giay Ipc tham khd dau Lay mudi ddng spch lau khd, cam xuyen qua tam bia, khdng d l mudi dong eham vao day binh (khoang... sat g) An toin thf nghiem - Khdng nen eat mau Na qua to, can xQ If Na sau tiln hanh thi nghiem, - Khdng dot ehay syi day sat, khdng dung maufrianqua Idn de lam moi, Cpo spch syi day sat Chf cho... Tdm l§i, TN hda hyc cd vai trd rit quan tryng dpy hpc • hda hpc Viec td chQc thyc hanh eae thf nghiem giang dpy hda hpe phd thdng la rat can thiet can dQdc quan lam dQng mQe PhO hdp vdi chien