Giáo trình vật lý đại cương phần nhiệt học vật lý phân tử ths nguyễn hoàng tuyến, ths nguyễn thị ngọc vân

BQ GIAO DUO VA DAO TAO TRUONG DAI HOC DAN LAP CtfU LONG Nguyen Hoang Tuyen - Nguydn Thi Ngoc Van Giao Trinh VAT LY DAI CU'O’NG • • Phan Nhiet Hoc & Vat Ly Phan TuT LiCu hanh noi bo SA thL vi£n i I Vlnh Long - 2009 Ldl DE TUA Trircrng Dai hoc Dan lap Cufu Long muon khang dinh la trung tam dao tao nguon nhan lilc co trinh cao cho khu vile dong bang song Cdu Long de phuc vu cho ebng cuoc cong nghiep hoa, hien dai hoa dat nifo’c thi phai nang cao chat hftfng dao tao toan dien Mot nhtfng yeu to yeu la doi ngu thay co, he thong cac giao trinh va trang thiet bi day hoc Cung vdi cdc nganh cac cap toan quoc dang day nhanh tien xay dang va cung co vi the xu the hoi nhap, triicrng Dai hoc Dan lap Cdu Long dan tiing bifdc hoan thien de difctag dau vcfi nhtfng thach thiic do, gop phan diia nen giao due dai hoc Viet Nam dufng vang, ngang tam khu vqc va the gidi Ke hoach xay dang ve mot Bo giao trinh sd dung cho cac giang vien lam tai lieu co ban de giang day, cho sinh vien nghien cdu tham khao hoc tap la nhu cau cap bach cua nha tradng An pham la giao trinh Vat Ly Dai Caong - Phan Nhiet Hoc & Vat Ly Phan Td cua Khoa Khoa Hoc Co Ban, Tradng Dai hoc Dan lap Cdu Long, ThS Nguyen Hoang Tuyen va ThS Nguydn Thi Ngoc Van bien scan Lanh dao tradng Dai hoc Dan lap Cdu Long tran nhdng cong hien, dong gop cua Quy thay cd mbi giang cung nha cac thay cd can bd - giang vien co' hdu cua nha trabng Hy vong rang, mot khong xa Trifcfng Dai hoc Dan lap Cufu Long se co day du mot Bo giao trinh hoan chinh dung nha trtfcfng Tran gidi thieu gido trinh den Quy thay co va cac em sinh vien triTbng Dai hoc Dan lap Cdu Long Vinh Long, thang 09 nam 2009 Q HIEU TRLfdNG ThS Nguyen Cao Dat t NHIET HOC Ccf hoc nghien ctfu nhtfng quy luat van dong don gian nhat cua vat chat, la sif chuyen dong cua vat the khong gian Khi khao sdt van dong co hoc, ta chOa quan tam den nhtfng hien tiTo'ng xay ben vat, ta chifa xet den nhtfng qua trinh cd lien quan den cau tao vat chat cua vat Thqc te cd rat nhieu hien tifOng lien quan den cac qua trinh xay ben vat Vi du : vat cd the ndng chay hoac bdc hoi bi dun ndng, vat se ndng len chiu life ma sat, Nhtfng hien tiTOng lien quan den mot dang chuyen dong dac biet cua vat chat, la chuyen dong nhiet Viec nghien cdu chuyen dong nhiet la nhiem vu cua bo mon Nhiet hoc Nhiet hoc Id ngdnh vat ly nghien cilu dang nhiet cua chuyen dong vat chdt vd nhUng quy luat cua chuyen dong Tuy nhien, nhiet hoc nghien cdu ca nhtfng hien tifqng dien, tit va nhieu hien tiTOng khac d cac vat Doi vdi nhilng hien tirqng nay, nd tien hanh nghien ctfu tren quan diem xet nhtfng dac diem cua dang chuyen dong nhiet Trong lich suf, nhiet hoc da xuat hien dau tien nhu" la nganh nghien cdu sif chuyen hda tir nhiet edng co hoc (may hoi nude), nen goi la nhiet dong life hoc Ve sau, cac dang khac cua nang lifOng (dien nang, hda nang, nang lifOng bdc xa, ) dan dan di/qc difa vao linh vifc nghien cdu cua nhiet dong life hoc, va bo mon cd the diXOc xem la khoa hoc ve nang IdOng VAT LY PHAN TLf Vat ly ph&n tic Id mot ngdnh vat ly nghien ciCu sU cdu thank vd cdc tinh chtit cua vdt chtit diCa tren co sd quan diem dong hoc phdn tic Theo quan diem nay, mot vat bat ky (cr moi trang thai ran, long, khi) khong la mot moi trirdng vat chat lien tuc, ma difoc cau tao tu" mot so" rat Idn cac hat rieng biet rat nho, goi la phan tih Cac phan tuf cua moi chat deu chuyen dong hbn loan khong ngiing, cifcfng chuyen dong phu thuoc vao nhiet cua chat < Vat ly phan th co muc tieu la giai thlch cac tinh chat cua cac vat cd the quan sat trite tiep tren thitc nghiem (ap suat, nhiet do, ) nhit la ket qua tac dung tong hop cua tap the nhieu phan tut Dong thdi nd sit dung phitOng phap thong ke, bang each khong quan tarn den sit chuyen dong cua tifng phan tut rieng biet ma chi quan tarn den cac gia tri trung binh dac trifng cho chuyen dong cua vd so hat Tit nd cd ten goi la vat ly thong ke Cung nhit nhiet dong life hoc, ddi titqng cua vat ly thong ke la nhitng quy luat cua dang chuyen dong nhiet cua vat chat Vat ly thong ke chi khac nhiet dong lite hoc ve phitong phap nghien cutu Trong nhiet dong life hoc khong ke den ban chat phan tu" cua cac chat thi vat ly th d'ng ke lai xuat phat tit ban chat nay, nd su* dung rdng rai nhitng dit kien ve cau tao phan tit va ap dung nhitng dinh luat ve xac suat Vat ly thong ke cho phep giai thich y nghia vat ly cua cac dai litqng nhiet dong, tim ditqc gia tri tuyet dd'i cua nhitng dai litqng ma nhiet dong lite hoc chi cho nhitng gia tri titong ddi < Chutcfng THUYET DONG HOC PHAN TLf VE CHAT KHI - KHf LY TtfdNG I THUYET DONG HOC PHAN Ttf VE VAT CHAT Vat ly phan til nghien ctfu cac hien tifcfng nhiet tren cP scr ly thuyet ve cau true hat cua vat chat, life tuPng tac gitfa cac hat va chuyen dong cua chung Ly thuyet duPc goi la thuyet dong hoc phan tuf Thuyet dpng hoc phan td Thuyet dong hoc phan tuf gom luan diem co ban sau : 1/ Vat chat difOc cau tao th vo so” cac phan td nhd be goi la phan tcf Phan td la phan to be nhd nhat co the phan chia dope td vat chat ma vdn gid nguyen moi tinh chat hda hoc cua vat chat ay Neu xet sau hOn, ta thay phan td co the phan chia cac nguyen td, nguyen td lai dupe cau tao td cdc hat: electron, proton va neutron (trong co cau hat nhan) Tuy nhien, d day chi xet cau true vat chat den mdc dp phan td ma thdi 2/ Phan td cau vat chat chuyen dong hdn loan khdng ngdng, goi la chuyen dong nhiet 3/ Trong qua trinh chuyen dong nhiet, cac phan td tuong tac va cham, chung hut hoac day Tuy trang thai vat chat la khi, long hay ran ma tUOng tac phan td cd the manh hay yeu Dien giai Cac so lieu sau day la bang chtfng xac minh sq dung dan cua cac luan diem cua thuyet dong hoc phan td : - So' luWng phan tuT mot khoi vat chat rat Idn Vi du, kmol khf bat ky co No = 6,023 x 1026 phan td (so Avogadro) - Rich thiTdc cac phan td rat be Neu coi phan td nhb mot qua cau thi difcfng kfnh cua no vao khoang 1O~10 m - Cac phan td khong nSm sat Do do, tong the tich rieng cua cac phan td nhd hcfn the tich cua toan bo vat Doi vdi chat long, tong the tich rieng cua cac phan td chiem khoang the tich toan bo Doi vdi chat khi, tong the tich rieng cua cac phan td chiem khoang 1/1000 the tich toan bo, cho nen kich thutfc phan td nhd thua hang chuc lan khoang each gitfa cac phan td - Moi phan td la mot he hat mang dien bi phan cite, vi vay chung tiTcfng tac life tinh dien veri Thifc nghiem cho thay theo khoang each r gitfa cac phan td, life tiTcfng tac phan td co the la life day hoac hut : r x IO-10 m cac phan td hut ; life hut giam nhanh r tang, d nhufng khoang each r > 15 x IO-10 m, life tifefng tac phan td rat nhd co the bd qua Nhir vay, d dieu kien ap suat va nhiet thirdng, ta cd the bd qua life hut gida cac phan td Vai hi£n tiTorng dien hinh phan anh dac diem can tao phan til cua vat chat a) Chuyen dong Brown Nhin cac hat phan hoa (kich thifdc vao ccf pm) nifdc qua kfnh hien vi, ta thay chung chuyen dong vdi quy dao la cac difdng gap khuc bat ky Chuyen dong goi la chuyen dong Brown Gidi thick : Chuyen dong Brown cd dude la chuyen dong hdn loan khong ngdng cua cac phan td ntfdc That vay, cac phan tii nifo’c chuyen dong, chung luon va cham vao cac hat phan hoa Vi cac hat phan hoa cd kich thifdc qua nhd nen cac va cham cua cdc phan th niftfc len chung khong khd l^n Do ngau nhien, so' va cham theo mot hifdng nao nhieu hon, ket qua la hat phan hoa se chuyen dong theo hildng Sau hat phan hoa di diTOc mot doan, no lai bi cac phan th nude day ve mot hu’o’ng khac Vi vay, quy dao cua cac hat phan hoa la cac dufrng zic-zac Ta co the ket luan : chuyen dong hon loan khong ngiTng cua cac hat phan hoa nifdc phan anh chuyen dong nhiet cua cac phan th nud’e b) Hien tityng khuech tan Nho mot giot thudc tim vao mot chen nude yen lang Thoat dau, ta thay vung mau tim rat hep va cd ranh gid’i ro ret dd'i vdi vung nude xung quanh De cang lau vung cd mau cang nhat, vung mau tim lan xung quanh va khong cd ranh gidi rd ret nhif trudc Vay, d day chuyen dong nhiet, cac phan td thudc tim va cac phan tuC mrdc da hoa lan vao Do la hien tirqng khuech tan phan tu* Vdi chat va chat rdn cung xay hien tdOng khuech tan phan td Vi du : bang phien khuech tan vao khong khi, dong va thiec tiep xue lau cung khuech tan vao II THUYET DONG HOC PHAN Thf VE CHAT KHI - KHI LY TLfdNG Mau ly tudrng Thuyet dong hoc phan tuf ve chat la sir van dung thuyet dong hoc phan tut vao viec nghien cdu chat Thuyet nghien ciiu chat bang edeh diTa mot “mo hinh chat khi” nham dd khao sat, goi la “mdu ly tirdng”, cd ap 110 b) Neu ap suat ban dau dr diem (1) la latm, hay tim ap suat va the tfch dr cac diem (2) va (3) Tfnh nhiet lifcmg tdi thieu can thiet de lam nong chay hoan toan 130g bac ban dau dr nhiet 15° C Biet rdng ddi vdi bac, nhiet nong chay la T* = 1235K , nhiet dung rieng va nhiet nong chay lan lutft la c = 236J / kg.K , L = 105 x 103 J / kg Mot vat Ididi lutfng kg rcri tu* cao 50m va nhb mot lien ket ccf hoc lam quay mot banh xe cd canh khuay 0,6 kg nutfc Nutfc ban dau dr 15° C Nhiet cao nhat ma nutfc len tdi la bao nhieu ? Mot que dun dien nhung nude dung de dun sdi 100 g nildc cho mot tdeh ca phe tan Que dien ghi 200W Tfnh thcri gian can thiet de difa nude tif 23° C tdi diem sdi, bo qua moi mat mat nhiet ludng Mot nhiet ke khdi lifdng 0,055 kg, nhiet dung rieng 0,837kJ/kg.K trd gia tri 15°C sau nd ditoc nhung toan bo vao 0,3kg nifdc, va nd chi cung mot nhiet cudi cung cua ntfdc Neu gia tri ma nhiet ke trd la 44,4° C, thi nhiet cua mfde trifdc nhung nhiet ke la bao nhieu ? Nhiet dung rieng cua mot chat thay ddi theo nhiet theo quy luat : c = 0,20 + 0,14T + 0,023T2 , vdi T tfnh theo °C va c tfnh theo cal/g.K Tim nhiet lifqng can thiet de nang nhiet cua 2g chat tif 5°C tdi 15°C 10 Mot bat bdng dong n&ng 150g dtfng 220g nifdc deu d nhiet 20° C Mot khdi dong hinh tru khdi lifPng 300g d nhiet Ill cao red vao bat ntidc lam nifdc sdi va bien 500g hoi Nhiet cuoi cua he la 100° C Hoi : a) Bao nhieu nhiet li/Ong da truyen cho niidc, cho bat ? b) Nhiet ban dau cua hinh tru la bao nhieu ? Chtfotag 3: Nguyen ly II Mot mol khf don nguyen td ly tiring thifc hien mot chu trinh nhif trinh bay tren hinh ve ben Qud trinh (b) - (c) la sir dan doan nhiet : = lOatm, = 10-3m3 , Vc = 8Vfo P(b) (a) (c) >V a) Tinh nhiet liftfng cung cap cho khoi khf b) Tinh nhiet litong khoi khf thai c) Tinh cong toan phan ma khoi khf thifc hien d) Hieu suat cua chu trinh Mot mol khf don nguyen td ly tifcfng dau tien cd the tfch 10 1, nhiet 300K difdc nung ndng dang tfch tdi nhiet 600K, sau dan doan nhiet tdi ap suat cuoi va cuoi cung lai diftfc nen ding ap tdi the tfch, ap suat va nhiet ban dau a) Tfnh nhiet ItTOng he nhan chu trinh b) Cong ma khoi khf thyfc hien chu trinh c) Hieu suat cua chu trinh la bao nhieu ? 112 T(K) 400 300 2000 0,2 0,4 0,6 S(J/K) Chilng minh rang chu trinh Carnot ve theo nhiet (nhiet giai Kelvin) la ham so cua entropy gian (S,T) thi ta di/crc mot hinh chu’ nhat Vdi chu trinh Carnot trinh bay tren hinh ve ben, tfnh nhiet liftfng nhan dutfc va cong thifc hien bdi he Mot mol ly lifting dcfn nguyen td diftfc dung lam tac nhan cua mot dong co nhiet theo chu trinh trinh bay tren hinh ve ben Gia sd P = Po, V = 2V0, Po = 1,01 x 105Pa va Vo =22,5 Tfnh : a) Cong thyc hien chu trinh b) Nhiet lifting he nhan qua trinh dan (a) - (b) - (c) c) Hieu suat cua dong ccr d) Hieu suat cua chu trinh Carnot neu dong co hoat dong gitfa hai nhiet cao nhat va thap nhat cua chu trinh tren So sanh nd vdi hieu suat tinh cau c P (brU (vo,Po)L (a) V 113 Mot mol khf ly tifdng dcfn nguyen tuf diroc chuyen tir trang thai dau co ap suat P, the tich V tdi trang thai cuoi co ap suat 2P va the tich 2V theo qud trinh khac • Qud trinh I : dan nd ding nhiet tdi cd the tich 2V, sau ap suat diftfc tang ding tich tdi trang thai cuoi • Qua trinh II : nen ding nhiet tdi ap suat tang gap ddi, sau tang the tich ding ap tdi trang thai cuoi a) Trinh bay dufrng di cua mdi qua trinh tren he toa PV b) V6i mdi qua trinh, tinh theo P va V : Nhiet luong hap thu bdi khdi mdi phan cua qua trinh Cong thcfc hien bdi khdi mdi phan cua qua trinh Do bien thien noi nang, bien thien entropy cua cac qua trinh 114 115 TAI LIEU THAM KHAO [1] David Halliday, Robert Resnick, Jearl Walker, “Co sd Vat ly”, ph&n Nhiet hoc, NXB John Wiley, 2000 [2] Dam Trung Don, Nguyen Viet Kinh, “Vat ly ph&n tit va nhiet hoc”, NXB Dai hoc va Trung hoc Chuyen nghiep, 1985 [3] Bui Trong Tuan, ‘Vat ly phan til va nhiet hoc”, NXB Giao due, 1999 [4] Le Van, ‘Vat ly ph&n til va nhiet hoc”, NXB Giao due, 1977 [5] Le VSn, Pham Viet Trinh, Nguydn Van Khanh, “Bai tap Vat ly dai citong”, tap I, NXB Giao due, 1982 [6] LilOng Duyen Binh, Nguyen HuU Ho, Le Van Nghia, Nguyen Tung, ‘Vat ly dai along”, tap I - Co Nhiet, NXB Giao due, 2003 [7] Ltfcfng Duyen Binh, Dang Quang Khang, “Bai tap Vat ly dai along”, tap I, NXB Gido due, 2003 [8] L E Irodov, “Tuy£n tap cdc bdi tap Vat ly dai along”, NXB Dai hoc va Trung hoc chuyen nghiep, 1985 [9] L V Xaveliev, “Giao trinh Vat ly Dai along”, tap I, NXB Dai hoc va Trung hoc chuyen nghiep, 1988 [10] Nguyen Dinh Hue, “Hod ly nhiet dong hie hoc hod hoc , phdn Co so, NXB Giao due, 1977 [11] Nguydn HuU Ho, Dang Quang Khang, ‘Vat ly dai along”, tdp I, NXB Dai hoc va Trung hoc Chuyen nghiep, 1982 [12] Nguyen Nhat Khanh, “Cdc bdi gidng ve co nhiet”, NXB DHQG Tp Ho Chi Minh, 2000 116 [13] Nguyen Thi Be Bay, Nguyen Dacfng Hung, (CVdt ly dai along”, Trifcfng Dai hoc Ky thuat Tp Ho Chi Minh, 2001 [14] Vu Thanh Khiet, “Nhiet dong lilc hoc vd Vat ly thong k&”, tap I, NXB Giao due, 1978 117 MUC LUC ChuWng THUYET DONG HOC PHAN TLf VE CHAT KHI KHILYTUdNG I Thuyet dong hoc phan tuf ve vat chat Thuyet dong hoc phan ttf Di£n giai Vai hien Wng dien hinh phan anh dSc diem cau tao phan td cua vat chat II Thuyet dong hoc phan td ve chat - khf ly tifdng M&u ly tifdng Dwn giai 10 PhiTOng trinh co ban cua thuyet dong hoc phan td khf ly tirdng HI Nhiet lirong - Nhiet 15 Nhiet lOo'ng 15 Nhiet 16 IV PhifOng trinh trang thai khf ly todng 18 V Cac dinh luat thifc nghiem ve chat khf 19 Dinh luat Boyle - Mariotte 20 Dinh luat Gay Lussac 20 Dinh luat Charles 21 Dinh luat Dalton 22 Bai tap chiTOng 23 ChWdng NGUYEN LY I NHIET DONG LUC HOC 26 118 I Nhiet nang cua ly tildng 26 Nhiet nang 26 So bac tit 26 Dinh luat phan bo deu dong nang phan td theo so bac tif 28 II Noi nang cua ly tifcrng 29 III Cong va nhiet 30 IV Trang thai can bang - Qua trinh can bang 31 Khai niem ve trang thai can bang va qua trinh can bang 31 Cong he nhan qua trinh can bang 32 Nhiet he nhan qua trinh can bang 34 V Nguyen ly I nhiet dong life hoc 35 Dinh luat bao toan va chuyen hoa nang litong 35 Nguyen ly I nhiet dong lufc hoc 36 He qua cua nguyen ly I nhiet dong life hoc 37 Dong co vinh cdu loai 38 VI I?ng dung cua nguyen ly I vdo cac qua trinh can bang dac biet 38 Qua trinh dang tich 38 Qua trinh dang ap 39 Qua trinh dang nhiet 40 Qua trinh doan nhiet 40 Bai tap chtfOng 42 ChuWng NGUYEN LY II NHIET DONG LUC HOC 47 119 I Nguyen ly I nhiet dong life hoc va chieu cua qua trinh 47 Sit truyen nhiet 47 Sq dan khf 47 Sir chuyen hoa tir ccr nSng sang nhiet nSng 48 II Qua trinh thuan nghich - Qua trinh khong thuan nghich 48 Qua trinh thuan nghich 48 Qua trinh khong thuan nghich 49 III Dong ccf nhiet 50 Dong ccf nhiet 50 Hieu suat cua dong cd nhiet 51 Dong cd vmh cdu loai II 52 IV Chu trinh Carnot - Dinh ly Carnot 52 Chu trinh Carnot (tac nhan la ly tufdng) 52 Dinh ly Carnot 55 Chu trinh bat ky 55 V Bieu thufe dinh liTcrng cua nguyen ly II 56 TriTcrng herp cd hai ngudn nhiet 56 TriTcrng htfp tong quat 57 VI Ham entropy - Nguyen ly tang entropy 58 Qua trinh thuan nghich 58 Qua trinh khong thuan nghich 60 Tong quat 61 Nguyen ly tang entropy 61 Vai tfnh chat cua entropy 62 120 VII Do bien thien entropy cua khf ly tPcrng cac qua trinh thuan nghich dac biet 63 Bai tap chifcfng 65 Chu’etag KHI THUG 69 I Life tifOng tac va the nang tifcrng tac gitfa cac phan td 69 Life tifefng tac phan tut 69 The nang tifong tac gitfa hai phan td 71 Qua trinh va cham gitfa hai phan tut 72 Dtfdng kinh hieu dung phan tut 73 II Phitong trinh trang thai khf there 73 Hieu chinh kich thifdc phan tut - Cong tich 74 Hieu chinh life hut gitfa cac phan tuf khf- Noi ap 75 Phifo’ng trinh Van der Waals 76 III Phuong trinh Van der Waals va ket qua thifc nghiem 77 Ho duefng dang nhiet Van der Waals 77 Ho dhefng dang nhiet thifc nghiem Andrews 78 So sdnh cac dudng dang nhiet Van der Waals va Andrews 80 81 Trang thai tdi han Bai tap chifo’ng 82 Chu’ctag CHAT LONG 83 I Nhtfng tmh chat chung va cau true chat long 83 Nhtfng tinh chat chung 83 Cau true phan tuf 83 II Hien tiTOng cang mat ngoai cua chat long 85 < 121 Hinh cau tac dung phan td - Ap suat phan ttf 85 Life c&ng mat ngoai 87 Nang lifting tif 88 III Hien lifting dmh ifdt 89 IV Ap suat phu gay bdi mat khum 91 Ap suat phu gay bdi mat khum 91 V Hien lifting mao d&n 94 Hien lifting mao dan 94 Do chenh lech gitfa hai mife chat long 94 Chiiting CHAT RAN 97 I Phan loai 97 II Chuyen dong nhiet tinh the - Sif dan nd vi nhiet cua chat ran 98 Chuyen dong nhiet tinh the 98 Sif dan nd nhiet cua vat ran 99 HI Nhiet dung rieng cua chat ran ket tinh 100 Hiking dan va dap sb 103 Bai tap bo sung 107 Chuting : Thuyet Dong hoc Phan tuf - Khi ly tifefng 107 Chuting 2: Nguyen ly I 109 Chuting 3: Nguyen ly II 111 TAI LIEU THAM KHAO 115 MUC LUC 117 122 i