VŨ ĐÌNH HOÀNG - · PDF file... LUYỆN THI ĐẠI HỌC VẬT LÝ CHUYÊN ĐỀ 9: 1 PHÓNG X Ạ, HẠT NHÂN VŨ ... công th ức bán kính R = 1,2.10-15 A3 1 m

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BI DNG KIN THC LUYN THI I HC VT L CHUYN 9: PHNG X, HT NHN 1
V NH HONG http://lophocthem.net
T: 01689.996.187 Email: [email protected]
H v tn:.......................................................................
Lp:.......................Trng...........................................................
BI DNG, LUYN THI VO I HC.
Thi Nguyn, 2012

MC LC
CH 1: I CNG V HT NHN NGUYN T
PHN I. KIN THC CHUNG: ..................................................................................................................... 3
PHN II. PHN DNG BI TP .................................................................................................................. 4
DNG 1. TNH BN KNH, TH TCH, KHI LNG RING CA HT NHN ........................................................................ 4 DNG 2: TNH S HT, T L PHN TRM NG V .................................................................................................. 5 DNG 3: TNH HT KHI, NNG LNG LIN KT, NNG LNG LIN KT RING ......................................................... 5
PHN III: TRC NGHIM TNG HP. .................................................................................................... 6
P N 37 .................................................................................................................................. 10
CH 2: PHNG X T NHIN
PHN I:KIN THC CHUNG. .................................................................................................................... 11
PHN II: PHN DNG BI TP: ............................................................................................................... 12
DNG 1: VIT PHNG TRNH, NU CU TO HT ................................................................................... 12 DNG 2: TNH LNG CHT PHNG X CN LI, PHN R, CHT MI TO THNH, T S PHN TRM GIA CHNG . ......................................................................................................................................... 13 DNG 3: TM PHNG X H, TH TCH DUNG DCH CHT PHNG X .................................................... 14 DNG 4: TNH CHU K T, HNG S PHNG X ...................................................................................... 15 DNG 5: TM THI GIAN PHN R T , TUI C VT ................................................................................... 16 DNG 6: TNH HIU IN TH BN T KHI CHIU TIA PHNG X. ............................................................. 18
III. TRC NGHIM TNG HP. ........................................................................................................... 18
P N 38 .................................................................................................................................. 23
CH 3: PHN NG HT NHN
PHN I. KIN THC CHUNG. ................................................................................................................... 23
PHN II: PHN DNG BI TP: ............................................................................................................... 23
DNG 1: VIT PHNG TRNH PHN NG HT NHN ............................................................................. 24 DNG 2: TNH NNG LNG CA PHN NG, LNG NHIN LIU CN T TO RA NNG LNG TNG NG. ............ 25 DNG 3: XC NH NG NNG, VN TC, GC CA CC HT ................................................................................. 27
PHN III. TRC NGHIM TNG HP. .................................................................................................. 30
P N S 39 ............................................................................................................................. 34
CH 4: PHN NG PHN HCH & PHN NG NHIT HCH NH MY IN HT NHN
PHN I. KIN THC CHUNG. ................................................................................................................... 34
PHN II. PHN DNG BI TP: ............................................................................................................... 36
PHN III. TRC NGHIM TNG HP................................................................................................... 36
P N 40 .................................................................................................................................. 43
HT NHN THI AI HC + CAO NG CC NM ............................................................................. 43
P N: PHNG X - HT NHN H C 2007-2012 ......................................................................... 50

PHN I. KIN THC CHUNG:
1.CU TO HT NHN NGUYN T . * Cu to ht nhn. Nucln + Ht nhn c cu to t nhng ht nh hn gi l cc nucln. C hai loi nucln: prton, k hiu p, khi lng mp = 1,67262.10
-27kg, mang mt in tch nguyn t dng +e, v ntron k hiu n, khi lng mn = 1,67493.10
-27kg, khng mang in. Prtn chnh l ht nhn nguyn t hir. + S prtn trong ht nhn bng s th t Z ca nguyn t trong bng tun hon; Z c gi l nguyn t s. Tng s cc nucln trong ht nhn gi l s khi, k hiu A. Nh vy s ntron trong ht nhn l: N = A Z. + K hiu ht nhn: XAZ . Nhiu khi, cho gn, ta ch cn ghi s khi, v k hiu ha hc xc nh Z ri. + Kch thc ht nhn: nu coi ht nhn nh mt qu cu bn knh R th R ph thuc vo s
khi theo cng thc gn ng: R = 1,2.10-15A 31
m. * ng v ng v l nhng nguyn t m ht nhn cha cng s prtn Z (c cng v tr trong bng h thng tun hon), nhng c s ntron N khc nhau. Cc ng v cn c chia lm hai loi: ng v bn v ng v phng x. Trong thin nhin c khong gn 300 ng v bn; ngoi ra ngi ta cn tm thy vi nghn ng v phng x t nhin v nhn to. * n v khi lng nguyn t Trong vt l ht nhn, khi lng thng c o bng n v khi lng nguyn t, k
hiu l u. Mt n v u c gi tr bng 12
1 khi lng ca ng v cacbon 126 C.
1u = 1,66055.10-27kg. Khi lng ca mt nucln xp x bng u. Ni chung mt nguyn t c s khi A th c khi lng xp x bng A.u. * Khi lng v nng lng H thc Anhxtanh gia nng lng v khi lng: E = mc2.
T h thc Anhxtanh suy ra m = 2c
E chng t khi lng c th o bng n v ca nng
lng chia cho c2, c th l eV/c2 hay MeV/c2. Theo l thuyt ca Anhxtanh, mt vt c khi lng m0 khi trng thi ngh th khi chuyn
ng vi tc v, khi lng s tng ln thnh m vi: m =
2
2
0
1c
v
m
trong m0 c gi l
khi lng ngh v m gi l khi lng ng. * Lc ht nhn
CH 1: I CNG V HT NHN NGUYN T

Lc tng tc gia cc nucln trong ht nhn l lc ht, gi l lc ht nhn, c tc dng lin kt cc nucln li vi nhau. Lc ht nhn khng phi l lc tnh in, n khng ph thuc vo in tch ca nucln. So vi lc in t v lc hp dn, lc ht nhn c cng rt ln (cn gi l lc tng tc mnh) v ch tc dng khi hai nucln cch nhau mt khong bng hoc nh hn kch thc ht nhn (khong 10-15 m). * ht khi v nng lng lin kt + ht khi ca mt ht nhn l hiu s gia tng khi lng ca cc nucln cu to nn ht nhn v khi lng ht nhn :
m = Zmp + (A Z)mn mhn + Nng lng lin kt ca ht nhn l nng lng to ra khi cc nucln ring l lin kt thnh ht nhn v cng chnh l nng lng cn cung cp ph v ht nhn thnh cc nucln ring l : Wlk = m.c
2.
+ Nng lng lin kt tnh cho mt nucln A
Wlk gi l nng lng lin kt ring ca ht nhn,
c trng cho s bn vng ca ht nhn. TM TT CNG THC .
Ht nhn XAZ , c A nuclon; Z prtn; N = (A Z) ntrn.
S ht trong m gam cht n nguyn t : N = ANAm
Lin h gia nng lng v khi lng: E = mc2.
Khi lng ng: m =
2
2
0
1c
v
m
.
ht khi ca ht nhn : m = Zmp + (A Z)mn mhn.N ng lng lin kt : Wlk = m.c
2.
Nng lng lin kt ring : = A
W lk .
n v khi lng nguyn t: 1u = 1,66055.10-27kg = 931,5MeV/c2.
PHN II. PHN DNG BI TP
Dng 1. Tnh bn knh, th tch, khi lng ring ca ht nhn Phng php:
cng thc bn knh R = 1,2.10-15A 31
m.
Th tch ht nhn coi nh hnh cu 34. .
3
RV
=
Khi lng ring hatnhanM
V =
VD1: Cho bit khi lng mt nguyn t Rai( Ra22688 ) l m(Ra) = 226,0254u; ca ht
eleectron l me = 0,00055u. Bn knh ht nhn c xc nh bng cng thc r = r0. 3 A = 1,4.10-15 3 A (m). Khi lng ring ca ht nhn Rai l A. 1,45.1015kg/m3. B. 1,54.1017g/cm3. C. 1,45.1017kg/m3. D. 1,45.1017g/cm3.

Gii Cng thc bn knh r = r0. 3 A = 1,4.10
-15 3 226 = 21,05.10-15m.
Th tch ht nhn coi nh hnh cu 34. .
3
RV
=
Khi lng ring hatnhanMV
= = 1,45.1017kg/m3.
DNG 2: Tnh s ht, t l phn trm ng v Phng php:
S ht trong m gam cht n nguyn t : N = ANAm
VD1. Kh clo l hn hp ca hai ng v bn l 3517 Cl = 34,969u hm lng 75,4% v 3717 Cl =
36,966u hm lng 24,6%. Tnh khi lng ca nguyn t ca nguyn t ha hc clo. GII
Ta c: mCl = 34,969u.75,4% + 36,966u.24,6% = 35,46u.
VD2. Bit NA = 6,02.1023mol-1. Tnh s ntron trong 59,5 gam urani 23892 U.
GII
Ta c: Nn = (A Z).m
NA = 219,73.10
23.

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VŨ ĐÌNH HOÀNG - · PDF file... LUYỆN THI ĐẠI HỌC VẬT LÝ CHUYÊN ĐỀ 9: 1 PHÓNG X Ạ, HẠT NHÂN VŨ ... công th ức bán kính R = 1,2.10-15 A3 1 m