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^Cac bai tap ve do tan dung boi diT&ng hpc sinh gioi Hoa THCS I KIEN THlTC CO BAN , I , Dinh nghla Do tan cda mpt chdt la so gam chat do co the hda tan trong 100 gam nudc dd tao thanh dung djch bao hd[.]
^Cac bai tap ve tan dung boi diT&ng hpc sinh gioi Hoa THCS T R A N T H I N G O C ANH Khoa Hoa hpc - Truang Dai hpc D6ng Thap I KIEN THlTC CO BAN , I, Dinh nghla: Do tan cda mpt chdt la so gam chat co the hda tan 100 gam nudc dd tao dung djch bao hda a nhiet do m„ C d n g thirc: S - — ^ 0 100 (C% la ndng dp % cua dung dich bao hda) 100-C% S 100 (C% la ndng dp % cua dung djch bao hoa) 100 + S II P H U O N G P H A P G U I BAI T^P Dang 1; Bai toan lien quan giira dp tan cua mpt chat va ndng dp phdn tram dung dich bao hoa cua chat Vi dy 1: 40"C dp tan cua K2SO4 la 15, Hay tinh ndng dp phdn tram cua dung dich K2SO4 bao hoa d nhiet dp nay? C% = w^^ - 100 +15 = 115gam ; C % = 15x100 13,04% Vi dy 2: Tinh tan cua Na2S04 d lO^C va nong dp phan tram cua dung dich bao hoa Na2S04 d nhiet dp B let rang d !0°C hoa tan 7,2g NaiSO^ vao 80g H26 thi duac dung djch bao hoa NajSO^, Dap sd: S = 9g va C% = 8,257%, S = 100;t7,2 = 9gam = 100 + = 109gam; C % = 9J;100 i,257% 109 Dang 2: Bai toan tinh luang chat tan tach hay them vao thay ddi nhiet mot dung dich bao hoa cho s i n Tru&ng hiyp /.' Khoi luang tinh the idch hay iheni vao khong ngam H^O Phuangplidp - Kh6i luong tinh thg tdeh ta hay them vao khong ngam H3O U kh6i Iugng H i O hai dung dich bao hoa b i n g Phucmg phdp gidi bai Igp linh khdi luang chdt tan can M vao flam nguac lgi vdi each gidi tim luang chdt kit linh) B,: Xac dinh nieiva m ^ Q co dd bao hoa nhiet dp th^ B J : Xac dinh nici CO dd bao hoa or nhiet ca (lugng nu6c khong d6i) B3: Xac djnh lupng chdt them vao ; M i , ( „ i , = m„ (nhiet t h i p ) - r o „ ( n h i ? t dp cao) j Vi dy I : Co bao nhigu tinh t h i NaCI tach Urn I?n ISOo'gam dung djch NaCI bao hoa tir 90°C dSn 0"C Bi dg tan cua NaCI o 90"C la 50 gam va cr 0"C la 35 gam Hu&ng din giii: ti 90°C co S - 50g nen la CO lOOg HjO + 50g NaCI tao ta 150g dd NaCI bao hoa Vay ? ? IgOOgddNaCIbaoho Suy ra: m „ „ = B2: Xac djnh ni,^cd dd bao hda nhiet dp thap (luang nudc khong doi) nt B,: Xac djnh lugfng chat ket tilth niKT = nici (nhiet dp cao) - m^, (nhiet thSp) Chily: - Khi lam l ^ h mpt dung dich bap hpa chSt tan rdn thi tan thuong giaiTi xuong, vi vay CO mot phin chit rdn Ichong tan bi tach (phan liet tinh) = 600g s u y r a m„_o - 1800-600 =1200g C) 0°C CO S = 35g CO nghra la lOOg HjO hoa tan dugc 35gNaa Vay n O O g H j O ? 1200x35 „„ , =420gZ 100 Kh6i lugng NaCI kjt tinh - 600g - 420g -180g^ Vi du 2: CJ 12''C CO 1335 gam dung dich bap h o i CuSOi Dun nong dung dich len d i n 90''C Hoi phai them vao iH djch bao nhieu gam CtiS04 nfta d l dugc dung djch b^ hoa o nhiet dp B i i t dp tan CuSO, o 12"C va 90°CBn l u g t l a 3 , g vaSOg Hudng dan giai: C) ° C c S = 33,5g OOg H2O + 33,5g CuSO,tao 133,5g dd CuSO, bfc ta 1335gddCuSO,baol* Vay niNaCi= gidi bdi tap linh khoi luang chdt li&l linh Bi: Xac djnh md va m^^ Q cd dd bao hoa d nhiet dp eao 1800x50 _ 1335x33,5 = 335g 133.5 lOOOg 1335335 = s u y r a l,i„^o a 90"C CO S = 80g CO nghia la lOOg HjO hoa tan dugc 80g CuSO, Vay lOOOgHjO ? 1000x80 SOOg "Ciiso • lOQ KhSi lugng CuSO^ cSn them de t^o dung dich bSo h6a d 9(fC mcso, =800-335=465g Suy ra: m,,„^ ( K i s a u : Tnring tiff