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De xuat bien phap phat then nang luc thirc nghiem cho hoc sinh thong qua day hpc phan Din xuat hidrocacbon Idp l i
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' V p Khoa htK Giao due Vigl Nam 101 Tifei Hung Bgo, Hoan Kigm, Ha Nfli, Viei Nam Email dao311@gniai com
Parang Tnjng hoc phd Ihfing TrSn Oang Ninh.
Ung Hoa, Ha NOI, ViK Nam Email hoangloantdn^gmail com
TOM T A T : Mdn Hda hoc la mon khoa hoc vda mang tinh 11 thuyet vOa mang tinh thuc nghiem nen viee hmh thanh va phat tndn nang iuc thue nghiem trong day hoc mdn Hda hoc la mdt trong nhdng yeu cau cap thiet. Tren co sd cau true cua nang luc thuc nghiem, bai bao de xuat mdt sd bidu hien va cac tieu chi cua nang iuc thuc nghiem, dong thoi de xuat each su dung thi nghiem trong day hoc ket hop vdi cac phuong phap day hoc tich cue: Su dung thi nghiem theo phuong phap nghien cuu, phat hien va giai quet van de, kiem chung, ddi chdng; Day hoc theo phuong phap ban tay nan bdt nham phat tridn nang luc thuc nghiem hda hoe cho hoc smh thdng qua day hoc phan din xuat hidrocacbon Idp 11
T i l KHOA. Nang l^c th^c nghiem; thuc nghiem; hgc sinh.
Nti3nbai 16/8/2018 NhankgtquaphanbienvachintisLia17/9/2018 " Duyeti3ang25/9/2018
I.Dat van die
Day hpc theo dinh hirong phat tnen natig lye (NL) nguai hoc la mot xu hLrong tit yeu cua nen giao due cac nuac tren the giai. Ngoai muc tieu phat tnen cac NL chung: NL tu chu va tir hoc, NL giao tiep va hop tac, NL giai quyet van de va sang tao [1], moi mon hgc can phat trien cac NL chuyen biet mon hpc: NL sir dung ngon ngu hoa hoc, NL vin dung Itien thirc hoa hoc vao thuc tien, NL thirc nghiem (TN) (NLTN),....
[2]. NLTN la mgt trong cac NL chuyen biet va NL chii dao cua mon Hoa hgc boi no la mon khoa hpc vira mang tinh h' thuyet vira mang tinh TN. Trong thirc te, viec phat trien NLTN trong day hpc mon Hoa hpc da dupe giao vien quan lam, song chua duac thyc hien thuong xuyen hoac dupe ihuc hien chua khoa hgc. Cu the: GV da sir diing thi nghiem nhung chi don gian la bieu dien cho hgc sinh (HS) quan sat, thi nghiem minh hoa cho cac linh chat hoa hgc. Viec sir dung thi nghiem kel hop voi cac phuang phap day hgc tich cue nhu the nao de phat tiien dugc NLTN hoa hpc ciia HS va each van dung vcri mot ngi dung cu the trong chuong trinh mon Hoa hpc van con la dieu kha kho doi voi giao vien Ngi dung bai viel de xuat mot so bien phap nham phat Irien NLTN cho HS thong qua day hgc phan Dan xual hidrocacbon lop I I .
2. Noi dung nghien cuu
2 . 1 . Nang l u c t h u c n g h i e m
Theo Tir dien Tieng Viet: "NLTN la kha nang van dung nhiing kien Ihuc, kinh nghiem, kT nang, thai do va hung thii de hanh dgng mot each phu hgp va co hieu qua trong cac tinh huong da dang ciia cupc s6ng". Theo chung toi: NLTN la kha nang van dung cac kien thuc, k! nang TN ciing vcn thai dp tich cue va hung thii d i giai quyll cac vkn di dat ra trong thirc tien mpt each phii hpp va hieu qua.
Cau tnic NLTN du kiin phat t n i n a HS bao g6m bon thanh t 6 [ 3 ] , [ 4 ] .
- Xac dinh van de va de xuat phucmg an TN: Xac dmh cau hoi/mue dich TN; de xuat cac du doan, de xuat gia thuyet TN; de xuat cac phuang an TN.
- Thiel ke phuang an TN: Phan tich va lira chon phuong an TN; Xac dinh doi tugng TN va lua chgn thiet bj, dyng cu, nguyen iieu de tien hanh TN; Bo tri/thiet ke TN va xac dinh quy trinh TN.
- Tien hanh TN: Chuan hi nguyen lieu, thiet hi, hoa chat, Su dung thigt hi, dung cu, hoa chat, Thue hien quy trinh TN;
Quan sal, ghi chep, thu thap thong tin.
- Xii li, phan tich, bao cao ket qua va nit ra ket luan: Xu li k i t qua TN; phan tich kSt qua TN; Bieu dien, trinh bay ket qua TN; Riit ra ket luan.
2 . 2 . Bieu h i e n va t i e u c h i cua nang luc t h u c n g h i e m Vai HS ph6 Ihong, NLTN hoa hgc la su van dung cac kien thuc hoa hgc, kl nang TN cimg vcri thai dp tich cue va hirng thii di giai quylt cac nhiem vu dai ra Irong qua trinh hpc tap va van di dat ra co lien quan den Ihuc lien mgl each phii hpp hieu qua NLTN hoa hgc dugc thi hien thong qua hoat dgng nhu sau:
1/ Giai thich dupe hien tugng trong dai song, trong tu nhien lien quan den hoa hgc.
2/ Thuc hien Ihanh eong cac thi nghiem.
3/ Chi tao cac dung cu thi nghiem hoat dpng dua tren nguyen lac, dinh luat lien quan den hoa hpc de phuc vu cugc song.
Nhu vay, NLTN gdn vai kha nang hanh dgng, doi hoi HS phai giai thich dugc, lam dugc, van dung duac kien thiic li t h u y a vao thuc tiln. Viee danh gia su phat trien NLTN ciia HS theo chiing toi dugc danh gia thong qua eac tieu ehi cho cac hanh vi (xem Bang i).
2 . 3 . M o t so b i e n phap p h a t t r i e n nang luc t h u c n g h i e m 2 . 3 . 1 . Sli d y n g thi n g h i e m trong day hoc ket hop vdi cac phuong phap day hoc tich cue
So 09, thang 09/2018 93
NGHllNCOrULiLUAN
Bang 1 : Cac tieu chi cho cac hanh vi de' danh gia su phat trien NLTN cua HS
Hinh thanh gia thuyet va cac phuong an TN
1 Xac dmh muc tieu, ntiiem vu cua TN _ 2- Oe xual cac du doan, gia tiiuyet 3 . D e x u a t c a c p t i u o n g a n T N Thigt ke'phuong an
thuc nghiem
4. Xac dmh nguyen lieu va thiet bi, hoa chSt de lam TN
Tie'fi hanh TN va thu thap ket qua
5- Oe xuat cac buoc tien hanh TN 6, Chon nguyen Ii6u, dung eg, hoa chat de JamTN
7. SD dung cac clung cu, hoa chat da lua chon de tien hanh cac buoc TN i. Thu thap thong tin, ket qua TN
X i i l i , phan tich, bao c a o k e t q u a T N va riit ra ket luan
9 Xu li, phan tich thong tin thu thap dupe de bieu dien ket qua TN
10. Riit ra ket luan
Thi nghiem hoa hpc se tao hung thii hgc tap cho HS, cho cac em cu the hoa eac kien thiic li thuyet bang cam nhan cu the:
Mdt thky tai nghe. Thi nghiem giiip cac em tin vao kien thirc li thuylt dugc hgc, giiip tu tim toi kien thirc, nh6 kien thuc lau hon. Tir do, cae em co niem tin vao khoa hgc, co hung thu va dam me kham pha cac mon khoa hgc, cu the la Hoa hoc.
Tuy nhien, thi nghiem hoa hoc khong chi dan gian la bieu dien thi nghiem cho HS xem, cung khong phai don gian la diing thi nghiem de minh hoa cac tinh chat cua eae chat - vi nhu vay HS vin tiep thu kien thuc mpt each thu dong, Thi
nghiem Irong day hoc hoa hgc se dugc coi la tich circ Rn ^ dimg lam ngii6n kiln thuc cho HS khai thac. tim kien thuc de kilm tra eac suy luan, du doan, hinh thanh khai mem... do chinh ta cac thi nghiem nghien cim, thi nghiem do HS lu len kl hoach va ihuc hien, tir do se phai tnin tit NLTN cho HS [5].
Muln lam dugc dilu do, thi nghiem hoa hgc can kel hop vai cac phuong phap day hpc lich cue. Cu the la:
a. Sir dung thi nghiem theo phuang phdp nghien cmi Trong day hoe hoa hgc, day hpc theo phuong phap nghien cuu dugc danh gia la phuang phap day hgc hieu qua, tich c\rc nhai vi no ren luyen dugc lu duy dpc lap sang tao, ren luyen cac ki nang nghien cini tim toi va khSc sau kien thiic eho HS.
Phuang phap nay cho HS buoc dSu lam quen vcn cac nghien Cliu khoa hge, tao say me va hirng thii hgc tap cho eac em.
* Sir dung thi nghiem hoa hgc theo phuang phap nghien cuu thi thi nghiem hoa hgc dugc coi nhu ngudn kien thiic mai dl HS nghien eiiu, tim toi, phuang lien xac nhan linh diing dan ciia gia thuylt, dir doan khoa hoc HS dugc huong din thuc hien theo cac buac cu thi, Minh hga cii the day hpc thi nghiem "Phan ling trang bac cua CH3CHO" theo phuong phap nghien cuu (xem Bang 2).
b. Sir dung thi nghiem theo phuong phdp phdt hien vd gidi quelvdn de
* Trong phuong phap day hgc phat hien va giai quyet van dl, khau quan trpng nhat la xay dung bai toan nhan thiic hay lao ra cac mau thuSn tinh hufing co van de Tir do de xuat cac phucmg an giai quyet van de, lap ke hoach thuc hien, danh gia kit qua va van dung vao cac linh huon tucmg tu,
* Viee sir dung thi nghiem hoa hpc phoi hgp vai phuong phap day hpc phat hien va giai quyet van de c6 the thuc hien a khau tao tinh huong eo van de hoac khi xay dung ke hoach
Bang 2: Minh hga day hoc thi nghiem "Phan dng trang bgc cua CH3CHO" theo phuong phap nghien cdu
C a c b u t c t l A i M m i G J i i i p h U d n g i l M p n g M e i i c i i u V l i l v c p M i « i p l i a i l i ) n g H n g b « i ; c i i a C H , C H O
- Buoc 1 . HS hieu va nhan bifit va'n de can nghien cUu. GV dat vSn de' Andehit co phan img vdi [Ag(NH3jj]0H} khong? Neu co san ph^m va ban cha't cua phan Ong la gi?
- Budc 2 D'e xuat cac gia thuyet, du doan khoa hoc tren co so kien thuc da cd.
H S O e xuat 2 kha nang:
- Cb phan img, do C trong nhom CHO co sd 0x1 hoa la +1, nen andehit cd linh khti tac dung duoc vdi chat 0x1 hoa manh la Ag^- sinh ra Ag
- Khong co phan Ung. ^^ ^ _ ^ - Budc 3. U p ke hogch giai ling vdi lUng gia thuyet - HS, De xuat phuong an tien hanh thi nghiem.
Lap phuong an tien hanh thi nghiem, du doan cac (GV bo' sung, dua ra chii y, GV tu van cho HS vi day la mot thi nghiem khd) hien tuong se quan sat duoc, giai thich va rut ra nhan - HS du doan hien tuong quan sat duoc: Cd kirn loai Ag sinh ra, vi day la phan Ung xet va rut ra hien tuong du kien oxi hda khu A g + b i khu thanh Ag
- Budc 4 Tien hanh thi nghiem, quan sat mo ta hien tuong quan sat duoc
- Buoc 5: Xac nhan gia thuyet, du doan phuong an dUng qua cac ket qua thi nghiem.
- GV hoac HS tien hanh thi nghiem.
- HS quan sat, mo ta hien tupng, giai thfch va vie't phuong trmh hoa hoc.
Andehit cd tinh khii ^ _ - HS xac nhan gia thuyet, CH3CHO cd tac dung voi AgNOj/NHj sinh ra Ag.
- Budc 6: Ket luan ve kien thUc thu nhan duoc Giai thich hien tuong, viet phuong trmh va rut ra ket Iugn.
HS ket luan, viet phuong trinh hda hoc.
94 TAP CHI KHOA HOC GIAO DUG VIET NAM
Pham Thi Bi'ch Dao, Pham Thi Hoang Loan
Bang 3: Cac budc thi n g h i e m GITeol tac dung vdi Cu(OH); theo phuong phap phat hien va giai quyet van dd
Cac M c tien hanh cua phuong Vi dv cu the M phan l i n g : Glixenl tac dgng vdi Cu(QH), phap phat Men va giai quyftvan de
- Buoc 1: Phat hien van de
- Budc 2: Phat bieu van d'e
- GV: Ancol etylic va glixerol co tac dung vdi Cu(OH)j khOng?
- HS dua ra mau thuan nhan thdc: Cting co cau tao nhom OH, ancol etylic khong tac dung duoc vdi Cu(OH)a, vay glixerol cd phan Ung khdng?
HS phat bieu thanh van d'e nghien cdu: Glixerol co phan Ung vOi Cu(OH); khdng?
- Budc 3.0'e xuat hudng giai quyet van d'e va thuc hien.
Ket luan van de
- HS d'e xuat hudng giai quygt bang each tifin hanh lam thi nghiem cua glixerol va ancol etylic vdi Cu(0H)2.
- HS len phuong an tie'n hanh va lam thi nghiem - HS thu thap ket qua, xac nhan gia thuyet va rUt ra ket luan - B u d c 4 : Van dung g
hudng tuong tu
i quyet cac tinh GV hdi Phan biet cac dung dich: propan -1 - o l va propan -1,2 - diol?
Bang ^ Cac buoc tien hanh cua phuong phap k i e m chung
- Budc 1" Nhan thOc rd van de hoc tap va nhiem vu dat ra,
- Budc 2; Neu cac ket luan, nhan xeL du doan ve kien thiic mdi, hien tuong ciia thi nghiem se xay ra.
- GV neu muc dich ciia thi nghiem. Axit cacboxylic co tinh axit nhu cac axit HCI, H^SOj loang da hoc khong?
- HS neu tich chat hda hoc chung ciia axit
- HS du doan ve tinh axit cOa axit cacboxylic: Co day du tinh chat nhu axit thong thuong + Ddi mau quy ti'm sang dd
+ Tac dung vdi kim loai trudc H giai phong H^
+ Tac dung vdi bazo, oxit bazo +Tac dung vdi mudi cua axit yeu hon - Budc 3: DS xuat cac thi nghiem can lam de
kie'm chdng, chuan bi dung cu, hda chat va cach tien hanh.
GV Vdi cac hda chat va dung cu da chua'n bi trudc Dung dich HCI 0,1 M, dung dich CH3COOH 0,1 M, dung dich NaOH, quy tim, Zn, Cu, CaCOj, dung dich phenolphtalem, dung dich CUSO4, may do pH. Hay lua chon dung cu, hda cha'L de xuat cac thi nghiem dting de' kie'm chdng tinh axit cua axit axetic,
- HS de xuSt cac thi nghiem, tu chon dung cu, hda chat va len phuong an tien hanh thi nghiem
- Budc 4: Tien hanh lam thi nghiem, quan sat, md ta hien tuong, xac nhan su ddng sai cua cac gia thuyet.
• HS tien hanh lam thi nghiem Thu thap ke't qua de xac nhan gia thuyet.
- Budc 5: Ke't luan, dua ra ke't qua nghien cdu | - HS ket luan ve tinh axit cua axit cacboxylic.
giai CO sir dung thi nghiem de xac nhan ket qua ciia qua trinh giai quySt van de. Chimg toi se phan tich cac buac day thi ngliiem Ghxerol tac dung voi Cu(0H)2 theo phuang phap phat hien va giai quyet van de (xem BSng 3)
* 'V nghia: Khi sir dung thi nghiem hoa hpc ket hgp vai phuong phap day hgc giai quygt vkn di, HS khic sau duac kien thirc, nam ki^n thuc mpt each bSn vung hon, d6ng thai phat huy dugc tinh chu dong tich cue eua HS. Digu quan trgng la qua qua trinh hgc tap, HS co kT nang va phuang phap ap dung de giai quyet cac vkn di trong thuc tign dai s6ng, phat trien NLTN hoa hgc, NL giai quyet van di trong thirc tiin.
c Sic dung thi nghiem theo phuang phdp kiim chimg
* Trong day hgc hoa hoc, su dung thi nghiem theo phuang
phap kiem chung co tac dung tich cue trong viec hinh thanh phuang phap nhan thuc, nghien cuu, hpc tap hoa hgc, phat trign NLTN, NL giai quygt vkn di cho HS. Trong phuang phap nay, HS se sir dung thi nghiem hoa hpc de kiem chimg lai cac nhan xet, cac gia thuySt khoa hgc theo li thuyet hoac cac v§n di nay smh trong thue tien co hen quan den hoa hpc.
Nhu vay, thi nghiem hoa hpc dugc coi la cong cu de xac minh tinh dung dJn cua gia thuyet, cac nhan xet, suy doan ciia cac nha khoa hpc, lam cho cac em tin hrong vao tinh diing dan cua khoa hgc, eho cac em them tm, yeu mon Hoa hgc hon.
Minh hga eu the cac buac tiin hanh giang day ve thi nghiem
"tinh axit cua axit cacboxylic" theo eac buac ciia phuong phap kiem chimg (xem Bang 4):
So'09, Ihang 09/2018 w
NGHIENCUTULILUAN
Bang 5 ' S d dung thi nghiem theo phuong phap del chdng
GV hoi Cho biet su gidng nhau va khac nhau vS cau tao phan tu benzen va phenol.
GV: Vay tinh chai cua vong bezen trong phan til benzen va trong phan td phenol cd khac nhau khong? Hay de xuat gia thuyet, de xuat phuong an TN de ddi chUng?
Hdi: Hay thao luan du doan hien luong, de xuat each tiS'n hanh thi nghiem?
GV: Ho tro digu chinh cho HS ve cac budc lam TN va cac chu y an toan + Ca'n than khi tiep xuc vdi phenol + Phan ung lam trong tu hot vi brom, benzen d i bay hoi, hoi doc
- GV td chuc cho HS lam thi nghiem, quan sat hien tuong, viet phuong trinh, so sanh va n i l ra ket luan
HS' Gidng la deu cd vdng benzen, khac la phenol cd nhonfi OH hen k§t vdi vdng benzen
- HS, phan dng dac trung cua vdng bezen la phan Ung the', De xuat phan ting voi dung dich Br^
- HS du doan hien tuong, de xuat doan each tien hanh + Cho vao 2 dng nghiem, moi dng khoang 2 ml dung d|Ch brom bao hda
+ Cho vao dng nghiem thU nhat vai tinh the phenol t Cho vao dng nghiem thU 2 khoang 2 ml beozen + Lac nhe cac hon hop phan dng
- Cac nhdm HS nhgn dung cu hda chat, lam thi nghiem - HS quan sat, thu thap ket qua, bao cao - H S viet phuong trinh
- HS rut ra ket luan- Nhdm OH lam tang kha nang phan ung the cua vdng benzen
BiSuhiSnciiaNLTII -OexuJit phuong an TN - X a c dmh dung cu, hoa chat, m d t a thiet ke thi nghiem -Thuc hien quy trmh TN - T h u thap thdng tm, ket quaTN - Bao cao, rdt ra ke't Iugn ve kie'n thdc.
Thi nghiem hoa hoc sir dung theo phuang phap kiem chimg thuong ap dung voi cac bai.
- Nghien cunj cac quy luat bien doi tinh chat cac chat tren ca sa li thuyet de xac nhan cac truang hgp trai quy luat, quy tac.
- Ki6m chirng tinh chat cua cac chat tren co sa du doan li thuygt trong cac bai day ve nguyen to, ve chat, khi nghien euu cac chat huu ca.
d Sirdung thi nghiem theo phuong phdp doi chimg Khi can lam chinh xac hoa mgt khai niem, mgt quy tac, quy luat... hay de lam noi bat, khac sau su khac nhau ciia cac kien thirc ma HS can nghien ciiu. Qua viec lua ehpn, tien hanh va quan sat, HS se rut ra dugc nhan xet diing dan, nam dugc phuang phap giai quyet van de bang TN. Khi sir dung thi nghiem theo phuang phap nay, GV can huong dan HS lira ehpn thi nghiem, du doan hien tugng thi nghiem, each tien hanh va thuc hien thi nghiem, quan sat va nit ra ket luan.
Vi du: Thi nghiem benzen, phenol tac dung voi dung dich Brom theo phuang phap doi chimg (xem Bang 5).
Can cir vao npi dung chuong trinh hda hpc ldp 9 cap Trung hgc ea sa, lap 11 co ban Trung hgc pho thdng va dieu kien thuc te cua cac phong thi nghiem, chiing toi da lira ehpn cac thi nghiem trong chuang 8, 9 ve Dan xuat hidrocacbon ciia chuang trinh ldp 11 co ban va de xuat cac bien phap day hpc tich cue khi day hoc cac thi nghiem nay
2 . 3 . 2 . Day hpc theo phuong phap ban tay nan bat nham phat tri^'n nang luc thuc nghiem hda hgc cho hoc sinh
Ban tay nan bgt (BTNB) la mgt phuang phap day hgc tich cue, HS phai tu minh giai quyet van de, qua do ma kien tao duge kign thirc luyen dugc ki nang. Diem dac biet a phuang phap BTNB la 2 buac diu tign: Tao tinh hu6ng xuk phat va cau hoi neu vin dg (buac 1), chii trgng tai viec bgc 16 quan digm ban dku cua HS, dg HS hinh thanh va phat bieu dugc cac bigu tugng/quan mem ban dau (budc 2) ve van dg hpc tap
hi do di xukt dugc cac cau hdi nghien ciru. Khi diuc hien 2 buac nay, HS phat trik dugc NL xac dinh van dg TN - mpt NL thanh phkn cua NLTN hoa hgc.
Ba buoc thuc hien tiep theo ciia phuang phap BTNB phat trign dupe hau hgt cac NL thanh phan khac eila NLTN.
Thigt kg phuang an TN; tiSn hanh TN; xir li phan tich bao eao kk qua TN va nit ra k6t luan. Do do, day hgc theo phuong phap BTNB phii hop vdii viec phat trign NLTN hoa hgc cua HS trong cac bai day ve chat co sir dung thi nghiem hoa hge. Chiing toi da nghien cim de vSn dung phucmg phap BTNB khi day hgc phin Tinh chkt hoa hoe ciia: Phenol, axit cacboxylic (sach giao khoa lop 11 co ban). Sau day, xin trinh bay, phan tich each ap dung phuang phap BTNB bpt voi tiet day ve "Tinh chat hoa hgc ciia axit cacboxylic"
de minh hpa.
Budc I: Tinh huong xual phat va cau hoi ngu van dg Tinh huong xuat phat hay tinh huong ngu van de la GV chu dgng dua ra mgt tinh huong dan dat vao bai hpc. Tinh huong xuat phat phai quen thupc, dem gian va gin gui voi HS. Tinh huong xuat phat se dupe long ghep voi eau hoi neu vin de.
d dau bai tinh chat ciia axit cacboxylic: GV gioi thieu mpt so mau vat nhu qua chanh, qua sau, qua khg... giim an, me va cho biet vi chua ciia cac loai qua thuc phim tren dugc gay ra bdi cac axit hiiu co gpi la axit caeboxyhc GV neu van de: Cac axit cacboxylic co tinh chat hoa hoc gi, co gi gidng va khac cac axit v6 co? HS ghi eau lioi bai hpc vao va thi nghiem, suy nghT, tim toi.
Bu-&c 2: Bpc 16 quan niem ban dau cua HS Mgt buac quan trgng, dac trung ciia phuong phap BTNB la HS dupe tu bgc Eg quan diem ban diu hay cac quan niem ban diu dk hinh thanh cac khai niem, gia thuylt Trone buoc nay GV can chiiy:
+ GV khuyen khich HS dua ra cac suy nghT, nhan thirc ban
96 TAP CHi KHOA HOC GIAO DUC VIET NAM
Pham Till Bich Bao, Pliam Thi Hoang Loan
Bang 6: Cac gia I h u y H va phuong an Uivc nghi§m Ctu hdi nghien cilu
cau hoi 1:
Axil cacboxylic la axit manh hay ygu so vdi cac axit vd co nhu HCI.HNOa?
Bia « « > « nghien ciHu
- Uen ket 0 - H trong nhdm COOH cua axit cacboxylic cd su phan cue ve phia 0 nhung do 0 lien kgt voi nguyen to C cd do am dien nhd (tinh phi kim yeu) nen kha nang tach H+ ygu.
- NhiSu axit hUu co cd the' an duoc, tdc la cd tinh axit yeu
Oo de so sanh pH hay kha nang dan dien cua 2 dung dich axit 1 axit manh nhu HCI, HNO3 voi 1 axit cacboxylic nhu CH3COOH ciing ndng dp moi de so sanh kha nang dien ii cua chdng.
cau hdi 2:
Axit cacboxylic cd tinh chat hda hoc Chung cua axit khdng?
- Axit cacboxylic cung cd day du tinh chat hda hoc cua axit ndi Chung, Vay cho axit cacboxylic tac dung vdi quy tim, bazo, oxit bazo, mud'i, kim loai.
- Cho dung dich CH3CO0H tac dung vdi;
+ Cu,Fe,A[,Zn + CaCOg, NajCOg + Cu(0H)2, NaOH + CuO, MgO + Quy t i m cau hdl 3:
Phan Ung hda hoc nao chdng minh duoc axit cacboxylic cd phan ling the ciia nhom OH, san pha'm cua phan dng la gi?
Cac axit cacboxylic tac dung dugc vdi ancol, tuong tu cac axit vo CO nhu HCI, HBr (da hoc d bai Ancol).
DUng thi nghiem cua axit cacboxylic CHjCOOH vdi ancol CjHjOH de nghien cUu,
dau vg su vat, hien tugng mdi trudc khi dugc hgc ve kien thiic do
+ HS CO the trinh bay van dg bang rdiieu each khac nhau:
Vi^t, ndi, ve...
+ Viee HS dua ra cac quan niem sai lam la dieu de hieu, GV can chii trong cac nhan thiic sai lam nay, de HS co the tu nhan ra va sira chiia. Chinh viec nhan sai lam se lam cho HS nha kien thirc sau sac vit chac chan hon.
GV neu eau hoi: Vigt cong thiic eau tao va cho bigt dac diem ciia eae lign ket H - O va C - O trong nhom COOH ciia axit? Tir do du doan axit cacboxylic co nhiJng tinh chat hda hgc gi? Tir cau hoi cua GV, ket hgp vai cac kien thirc va kT nang da biet, ca nhan HS dua ra cac quan niem ban dau ve tinh chat ciia axit cacboxylic. Sau do, HS thao luan trong nhdm de dua ra quan niem ban dau thong nhat eiia nhdm. Tir eac quan mem ban dau tren, cae nhom thao luan de xuat cau hdi nghign eiiu dg lam ro tuih chat hoa hgc ciia axit cacboxylic. Ngi dung eae cau hoi ed thg la:
Cdu hot / : Axit cacboxylic laaxitmanh hay yeu so vai cac axit vo eg nhu HCI, HNO3?
Cdu hoi 2: Axit cacboxylic eo tinh chat hoa hoc chung ctia axit khong?
Cdu hoi 3: Phan img hoa hpc nao chung minh dugc axit cacboxylic co phan ling the cua nhom OH, san pham ciia phan ling la gi?
Budc 3: Dg xuat cac gia thuyet va thiet kg cac p h u a n g anTN
+ De xuat gia thuyet: Ung vai mdi cau hoi nghien ciiu HS de xuit it nhat mgt (hoac co thg nhigu) gia thuyet. GV h u a n g dan cac nhom thao luan de thong nhat dua ra cac dg xuat.
+ Thigt ke cac phuong an TN. Tir eac cau hoi de xual, GV yeu cau HS de xuat thi nghiem (chgn thi nghiem, hoa chat, dung cu, neu each tien hanh) de tim ra cau tra loi cho cac cau hoi do (GV ghi len bang cac de xuit cua HS cho khoi
triing lap). Khuygn khich t6i da tu duy phe phan, cho HS tu danh gia nhau han la GV danh gia. Sau do, GV neu nhan xet chung va quyet dinh phucmg an TN da chuan bi san. Trong tnrcmg hgp HS kh6ng neu ra dugc phuang an TN, GV co the ggi y hay dg xuat phuong an ngu sau khi da gpi y ma HS vin khong nghT ra.
Moi nhom HS co the dua ra cac de xuat Ichac nhau va len phuang an TN khac nhau, do la su sang tao, the hien sir da dang phong phu ciia tu duy HS.
Vai bai Tinh chat hoa hgc ciia axit cacboxylic, tucmg img vai cac cau hoi nghien cim tren, HS cd thg dua ra cac gia thuyet va len cac phuong an TN nhu sau (xem bang 6):
Bu-&c 4: Tien hanh TN tim toi - nghien cim GV ygu cau HS cho biet muc dich, eac tign hanh cac thi nghiem, sau do mai phat dung cu hoa chat. GV co the nhae nha, dua ra cac chii y can thigt khi lam thi nghigm an toan va thanh cong.
HS tien hanh lam thi nghiem, thu thap ket qua, xir li sa bp dg khdp vdi kgt qua can nghien cuu. Neu ket qua khong phii hgp, cin quay lai budc 3 - xem xet lai phucmg an TN,
HS c6 thg diing Idi hoac hinh ve de m6 ta kgt qua thi nghiem.
H6n hgp H2SO4 dac, CH3COOH, C^HjOH
Co miii tham bay ra, them nudc lanh vao dng nghiem thay chat long phan thanh 2 ldp.
Sd 09, thang 09/2018 97
NGHIEN curu Li LUAN
Buac 5: Bao cao kgt qua va dua ra kien thiic mdi Sau khi TN tim toi, nghign cim. cae cau hoi de xuat dan dugc giai quyet, cac gia thuyet duac kiem ehiing, cac ngi dung kien thirc dugc hinh thanh, GV cho mgt vai nhdm HS bao eao ket qua TN, khuyen khich cac nhom HS doi chigu vai cac y kien ban dau (d budc 2) sau do GV kgt luan chung.
GV tdm tit lai, he thdng lai de HS ghi vao vd eoi do la kign thire ciia bai hgc.
Trong bai Tinh chit hda hoc ciia axit cacboxylic, cac ket luan HS dua ra la:
I Axit cacboxylic la cac axit yeu, cd day dii tinh chat hoa hgc chung ciia axit:
• Dien li yeu ra ion H+
- Lam quy tim hda do
- Tac dung vdi baza, oxit bazo thanh muoi va nudc
- Tac dung vdi kim loai trudc H giai phong H - Tac dung vdi muoi cua axit ygu hon 2. Cd phan ling thg nhdm OH: Tac dung vdi tac H2SO4 dac tao este.
ancol (cd xiic
3. Ket ludn
SO- dung thi nghiem kgt hgp vdi cae phuong phap day hge tich cue va van dung phuong phap BTNB trong day hoc mon Hda hpc nhim giup HS nSm kign thii;c mot each day dii va sau sic ban, HS phat trign dugc mgt s6 NL va tang hiing thii hoc tap. Ddng thcri cac bien phap trgn giiip HS phat trien NLTN tren diy du cac phuang dien: Nghien ciru va thye hanh thi nghiem. Vdi each hgc nay, HS duge lam quen din vdi phuang phap nghien ciiu khoa hgc, se khdi nguon va tao eac kT nang, NL dl tu nghien ciiu trong tuang lai.
T^i li^u tham khao
[11 Bo Giao due va Dao tao, (2017), ChUdng trinh gido due phd thdng tdng the. Ha Npi.
|2j Nguyen Thi SClu, Phdt trien ndng lUc lioc sinh thdng qua day hoc hoa hoc, Tai lieu dao t?o Thac si Hoa hpc, Tnidng Dai hoc SU phpn H i Noi.
[3] Dang Thi Oanh - Pham Thi Bich Dao. (2017), De xudt cau triic vd ddnh gid ndng lUc thUc n^iem cho hoc sinh thdng qua mdn Khoa hoc Tu nhien cap Trung hoc cd sd, Tap chi Khoa hpc, TnJdng Dai hoc Sil pham Ha Npi.
[4] Nguyen Thi Lan Phildng (chil bi^n), (2016), ChUdng trinh tiep can ndng lUc vd ddnh gid ndng lUc ngUdi hoc, NXB Giao due. Ha Noi.
15] Dang Thi Oanh - Nguyen Thi Siiu, (2014), PhUdng phdp day hgc mdn Hoa hoc d trUdng trung hoc phd thdng NXB Dai hpc SiT pham, HiNoi,
[6] IsJguyen \ ^ Bien, (2013). Xay dUng chuyen dethi nghih tao nang lUc thUc nghiem cho hgc sinh trung hoc pho thong chuyen.
Tap chi Giao due, so dac biet
[7] Nguyen CiTdng (chu bien) - NguyIn Xuan TrUcmg - Nguyen Thi Sflu - Dang Thi Oanh - Tran Trung Nmh - Nguy&n Mai Dung - Hoang Van C6i - Nguyen Diic Diing, (2014), Thi nghiem thUc hdnhphUOng phdp day hgc hda hgc (PhUdngphdp day hgc hda hgc - Tdp III), NXB Dai hoc SU pham Ha Noi.
[8] VHTien Tmh, (2017), Sd dung phudng tien trUcquan trong day hoc mdt so khdi mem hda hoc cd bdn d trUdng trung hoc cd sd nhdm phdt tnen ndng lUc thUc nghiem cho hoc sinh, NXB Dai hpc Sit ph^im Ha Noi.
[9] Cao Thi Thang - Pham Thi Bich Dao, (2014). Budc dau dp dung phUdngphdp bdn tay nan bdt theo hudngphdt trien ndng lUc sang tao cho hoc smh trung hoc pho thdng trong day hgc hda hoc. Vien Khoa hoc Giao due Viet Nam.
PROPOSING THE MEASURES TO DEVELOP EXPERIMENTAL COMPETENCE FOR STUDENTS BY TEACHING THE HYDROCARBON DERIVATIVE AT GRADE 11
Pham Thi Bich DaaV Pham Thi Hoang Loan^
' The Vielnam National Inslitite ol Educaiional Sciences 101 Tran Hjng Dao, Hoan Kiem, Hanoi, Vielnam Email dao311@9mai com
^Trar Dang Ninh High School Ung Hoa, Hanoi, Vietnam Email lioang!o3ntdn@gmail com
ABSTRACT; Chemistry is not only a theoretical subject but also an experimental one.
so developing expenmental competence in teaching chemistry is one of the urgent demands. Based on the structure of experimental competence, the article concentrates on proposing some expressions and criteria of experimental competence, as well as the application of experiments in teaching combined with active teaching methods;
Using expenments in research methods, detecting and solving problems verifvinq, and controlling. Using Hands-on teaching methods to develop chemical experimental competence for students by teaching the hydrocadjon derivative at grade 11 K E Y W O R D S : Experimental competency; e x p e r i m e n t s .
98 TAP CHI KHOA HOC GIAO DUC VIET NAM