4 piv txwv ntawm cov lus nug txog qhov kub thiab lub peev xwm kub tshwj xeeb
1. Thaum ziab ua ke hauv lub hnub kub, txhuas los yog tooj liab, yam twg kub sai dua? Lub cua sov tshwj xeeb ntawm txhuas = 900 J/kg o C thiab lub cua sov tshwj xeeb ntawm tooj liab = 390 J/kg o C.
Kev Sib Tham
Qhov kub tshwj xeeb ntawm ib yam khoom ntau dua, nws yuav siv sijhawm ntev dua rau yam khoom kom sov, ntawm qhov tod tes, qhov kub tshwj xeeb me dua ntawm ib yam khoom, nws yuav sov sai dua.
Qhov kub tshwj xeeb ntawm tooj liab me dua li qhov kub tshwj xeeb ntawm txhuas, yog li ntawd tooj liab kub sai dua.
2. Ib yam khoom uas hnyav 2 kg nqus tau 100 calories ntawm cua sov thaum nws qhov kub hloov ntawm 20 o C mus rau 70 o C. Qhov kub tshwj xeeb ntawm yam khoom yog...
Kev Sib Tham
Nws paub tias:
Qhov hnyav (m) = 2 kg = 2000 gr
Kub (Q) = 100 calorie
Kev hloov pauv kub (Δ T) = 70 o C – 20 o C = 50 o C
Nug: Qhov kub tshwj xeeb ntawm yam khoom (c)
Lus teb:
c = Q / m Δ T
c = 100 calorie / (2000 gr)(50 o C)
c = 100 calorie / 100.000 gr o C
c = 10 2 calorie / 10 5 gr o C
c = (10 2 calorie)( 10 -5 gr -1 o C -1 )
c = 10 -3 cal gr -1 o C -1
c = 10 -3 cal/ gr o C
Qhov kub tshwj xeeb ntawm cov khoom yog 10 -3 cal/gr o C
3. Lub cua sov tshwj xeeb ntawm dej yog 4180 J/kg C o . Lub peev xwm cua sov ntawm 2 kg dej yog…..
Kev Sib Tham
Nws paub tias:
Cov cua sov tshwj xeeb ntawm dej (c) = 4180 J/kg C o
Qhov hnyav (m) = 2 kg
Nug: Lub peev xwm cua sov (C)
Lus teb:
C = mc
C = (2 kg) (4180 J/kg C₂O₃ )
C = (2)(4180 J/ C₂O )
C = 8360 J/ C₂O
4. Lub cua sov tshwj xeeb ntawm txhuas yog 900 J/kg C o . Lub peev xwm cua sov ntawm 2 grams ntawm txhuas yog…..
Kev Sib Tham
Nws paub tias:
Cov cua sov tshwj xeeb ntawm txhuas (c) = 900 J/kg Co₂O = 9 x 10₃2 J /kg Co₂O
Qhov hnyav (m) = 2 grams = 2/1000 kg = 2/10 3 kg = 2 x 10 -3 kg
Nug: Lub peev xwm cua sov (C)
Lus teb:
C = mc
C = (2 x 10 -3 kg)( 9 x 10 2 J/kg C o )
C = 18 x 10 -3 x 10 2 J/C o
C = 18 x 10 -1 J/ C₂O
C = 1,8 J/ C₂O
