Ukuqonda Izimiso Zabamnyama
Uma sixuba amanzi ashisayo nabandayo esitsheni esivulekile (isibonelo, ibhakede), ukushisa kuyadlula kusuka emanzini ashisayo kuya emanzini abandayo. Ngenxa yokuthi isitsha sivuliwe, okunye ukushisa kuyadlula emoyeni. Isitsha siyafudumala futhi. Ukushisa okukhishwa ngamanzi ashisayo akugcini nje ngokumuncwa ngamanzi abandayo kodwa futhi nomoya kanye nesitsha. Kulokhu, ibhakede liyisistimu engahlukanisiwe.
Uma sixuba amanzi ashisayo nabandayo ku-thermos evaliwe, ukushisa kuyadlula kusuka emanzini ashisayo kuya emanzini abandayo. I-thermos iyisistimu ehlukanisiwe , ngakho akukho ukushisa okudluliselwa emoyeni noma ku-thermos. Ukushisa okukhishwa ngamanzi ashisayo kumane kumuncwa ngamanzi abandayo kuze kube yilapho ingxube ifinyelela ukulingana kokushisa.
Isimiso sikaBlack sithi ohlelweni oluvaliwe oluhlukanisiwe, ukushisa okukhishwa yinto enokushisa okuphezulu = ukushisa okumuncwa yinto enokushisa okuphansi.
Ifomula eyisisekelo kaBlack
Qicishiwe =Qmunca
Incazelo: Qicishiwe = ukushisa okukhishwe yinto eshisa kakhulu, Qmunca = ukushisa okumuncwa yizinto ezishisa kancane.
Imibuzo eyisibonelo eyinhloko kaBlack
1. Ucezu lwensimbi eshisayo olunesisindo esingu-1 kg kanye nokushisa okungu-100 oI-C ifakwa esitsheni esiqukethe amanzi anesisindo esingu-2 kg kanye nokushisa okungu-20 oC. Lingakanani izinga lokushisa lokugcina lengxube? Ukushisa okuqondile kwensimbi = 450 J/kg Co, ukushisa kwamanzi okuthile = 4200 J/kg Co.
Ingxoxo:
I-Diketahui :
insimbi m = 1 kg, Tinsimbi = 100 oC, m amanzi = 2 kg, Tair = 20 oC, c insimbi = 450 J/kg Co, c amanzi = 4200 J/kg Co.
Kubuziwe :
Ingxube ye-T?
Jawab :
Insimbi inokushisa okuphezulu kunamanzi ngakho insimbi ikhipha ukushisa, amanzi amunca ukushisa.
(m)(c)(i-delta T) = (m)(c)(i-delta T)
(1)(450)(100-T) = (2)(4200)(T-20)
(450)(100-T) = (8400)(T-20)
45000 – 450T = 8400 T – 168000
45000 + 168000 = 8400 T + 450 T
213000 = 8850 T
T = 213000 : 8850
T = 24 oC
Suhu Izinga lokushisa lokugcina lenhlanganisela yensimbi eshisayo namanzi abandayo uma kokubili kusesilinganisweni sokushisa lingu-24 oC.
2. Umbuzo Wokuhlolwa Kazwelonke We-SMA/MA We-Fiziksi ka-2015/2016 No. 20
Amagremu angu-75 amanzi ekushiseni okungu-0 ° C axutshwa namagremu angu-50 amanzi ukuze izinga lokushisa lengxube libe ngu-40 ° C, ngakho izinga lokushisa lokuqala lamagremu angu-50 amanzi...
A. 125 o C
B. 120 o C
C. 110 o C
D. 100 o C
E. 80 o C
Ingxoxo
Kuyaziwa ukuthi:
Isisindo samanzi 1 (m1 ) = 75 amagremu
Izinga lokushisa lokuqala lamanzi 1 (T 1 ) = 0 o C
Isisindo samanzi 2 (m2 ) = 50 amagremu
Izinga lokushisa lokugcina lengxube (T) = 40 o C
Amayunithi obunzima ayafana ngakho-ke akukho ukuguqulwa okudingekayo.
Okufunwayo: Izinga lokushisa lokuqala lamanzi 2 (T 2 )
Impendulo:
Isimiso sikaBlack sithi ohlelweni oluvaliwe oluhlukanisiwe, ukushisa okukhishwa yinto enokushisa okuphezulu kufana nokushisa okumuncwa yinto enokushisa okuphansi.
I-Q ikhishwe = I-Q imuncwe
m 1 c ( Δ T 1 ) = m 2 c ( Δ T 2 )
Ukushisa kwamanzi okuqondile kuyafana ngakho u-c ukhishwa kulesi sibalo.
m 1 ( Δ T 1 ) = m 2 ( Δ T 2 )
(75)(40 – 0) = (50)(T 2 – 40)
(75)(40) = (50)(T 2 – 40)
3000 = 50 T 2 – 2000
3000 + 2000 = 50 T 2
5000 = 50 T 2
I-T 2 = 100
Impendulo efanele ngu-D.
3. Umbuzo Wokuhlolwa Kazwelonke We-SMA/MA We-Fiziksi We-2015/2016 Inombolo 20
Insimbi engamagremu angu-200 ishiswa ibe ngu-120 o C bese ifakwa kumagremu ayi-100 amanzi ekushiseni okungu-30 o C. Ngemva kokulingana, izinga lokushisa lengxube liba ngu-60 o C. Uma ukushisa kwamanzi okungu-4200 J.kg -1 o C -1 , khona-ke ukushisa kwensimbi okungu-...
A. 10,5 J.kg -1o C -1
B. 105 J.kg -1o C -1
C. 150 J.kg -1o C -1
D. 1050 J.kg -1o C -1
E. 1500 J.kg -1o C -1
Ingxoxo
Ukuguqulwa kwamayunithi esisindo kusuka kumagremu kuya kumakhilogremu (Uhlelo Lwamazwe Ngamazwe Lwamayunithi)
Kuyaziwa ukuthi:
Isisindo sensimbi (m 1 ) = 200 amagremu = 0,2 kg
Izinga lokushisa lensimbi (T 1 ) = 120 o C
Isisindo samanzi (m2 ) = amagremu ayi-100 = 0,1 kg
Izinga lokushisa lamanzi (T2 ) = 30 o C
Izinga lokushisa lokugcina lengxube (T) = 60 o C
Ukushisa kwamanzi okuqondile (c 2 ) = 4200 J.kg -1 o C -1
Kubuziwe: Ukushisa okukhethekile kwensimbi (c 1 )
Impendulo:
I-Q ikhishwe = I-Q imuncwe
m1 c1 (ΔT1) = m2 c2 (ΔT2)
(0,2)(c 1 )(120 – 60) = (0,1)(4200)(60 – 30)
(0,2)(c 1 )(60) = (0,1)(4200)(30)
12 c 1 = 12600
c 1 = 12600 / 12
c 1 = 1050
Impendulo efanele ngu-D.
4. Imibuzo Yokuhlolwa Kazwelonke Ye-SMA/MA ka-2018
Ama-250 ml amanzi abilayo (100 o C) athelwa epanini eliqukethe ama-400 ml amanzi ekushiseni okungu-35 o C. Ngemva kokulingana kokushisa, izinga lokushisa lengxube li... (ukushisa okuthile kwamanzi 1,0 cal.gr -1 . o C -1 )
Ingxoxo
Kuyaziwa:
Izinga lokushisa lamanzi ashisayo = 100 o C
Umthamo wamanzi ashisayo = 250 ml = 0,25 litre = 0,25 dm 3 = (0,25)(1000 cm 3 ) = 250 cm 3
Izinga lokushisa lamanzi abandayo = 35 o C
Umthamo wamanzi abandayo = 400 ml = 0,4 litre = 0,4 dm 3 = (0,4)(1000 cm 3 ) = 400 cm 3
Ukushisa kwamanzi okuqondile = 1,0 cal.gr -1 . o C -1
Ubuningi bamanzi = 1 gr/ cm3
Kubuziwe: Izinga lokushisa elihlanganisiwe
Impendulo:
Bala isisindo samanzi ashisayo nabandayo usebenzisa ifomula yobuningi:
m = ρ V
m = isisindo, ρ = ukuminyana, V = ivolumu
Isisindo samanzi ashisayo: m = ρ V = ( 1 gr/cm 3 )(250 cm 3 ) = 250 amagremu
Isisindo samanzi abandayo: m = ρ V = ( 1 gr/cm 3 )(400 cm 3 ) = 400 amagremu
Bala izinga lokushisa lenhlanganisela usebenzisa ifomula kaBlack eyinhloko:
Ukushisa okumuncwa ngamanzi abandayo = ukushisa okukhishwe ngamanzi ashisayo
mc Δ T = mc Δ T
Ukushisa okuqondile kuyafana ngakho-ke kuyasuswa kulesi sibalo.
m Δ T = m Δ T
(400)(T-35) = (250)(100-T)
400T – 14000 = 25000 – 250T
400T + 250T = 25000 + 14000
650T = 39000
T = 39000 / 650
T = 60 o C
