5 Egzanp pwoblèm chalè
1. Eten ki peze 2 kilogram gen yon chalè espesifik 130 J.kg -1 C -1 . Kantite chalè eten absòbe pou ogmante tanperati li soti nan 50 oC pou rive nan 100 oC se….
Pembahasan
Li konnen ke:
Mas (m) = 2 kg
Chalè espesifik eten (c) = 130 J.kg -1 C -1
Chanjman tanperati (Δ T ) = 100 oC – 50 oC = 50 oC
Kesyon: Chalè (Q) ki absòbe pa eten
Repons:
Fòmil chalè:
Q = mc Δ T
Deskripsyon: Q = chalè, m = mas, c = chalè espesifik, Δ T = chanjman nan tanperati
Chalè absòbe pa fèblan:
Q = (2 kg)(130 J.kg -1 C -1 )(50 ° C)
Q = (100)(130)
Q = 13000 Joule
Q = 1,3 x 10³ Joule
2. Kuiv ki gen yon chalè espesifik 390 J kg -1 o C -1 sibi yon chanjman tanperati 40 o C. Si chalè kuiv la absòbe pandan chanjman tanperati a se 200 kalori, alò mas kuiv la se...
Pembahasan
Li konnen ke:
Chalè espesifik kwiv (c) = 390 J kg -1 o C -1
Chanjman tanperati (Δ T) = 40 oC
Chalè (Q) = 40 Joules
Kesyon: Mas (m) kwiv
Repons:
Q = mc Δ T
40 = (m)( 390 )(40 ° C)
40 = (mèt)(390 )(40)
40 = (m)( 390 )(4)
40 = (m)( 1560 )
m = 40 / 1560
m = 0,026 kg
Mas kwiv la se 26 gram.
3. Dlo ki gen yon mas 20 gram ak yon chalè espesifik 1 kal g -1 oC -1 okòmansman gen yon tanperati 30 oC . Detèmine chanjman nan tanperati dlo a si kantite chalè dlo a absòbe a se 300 kalori!
Pembahasan
Li konnen ke:
Mas (m) = 20 gr
Tanperati inisyal (T1 ) = 30 ° C
Chalè espesifik dlo (c) = 1 kal gr -1 o C -1
Chalè (Q) = 300 kalori
Kesyon: Chanjman nan tanperati dlo a
Repons:
Q = mc Δ T
Q = mc ( T2 – T1 )
300 kalori = (20 gr)( 1 kalori gr -1 o C -1 )(T 2 – 30 o C)
300 = (20)(1)(T2 – 30)
300 = 20 (T2 – 30)
300 = 20 T 2 – 600
300 + 600 = 20 T²
900 = 20 T²
T2 = 900 / 20
T2 = 45 ° C
Chanjman tanperati:
ΔT = 45 ° C – 30 ° C
ΔT = 15 ° C
4. Kantite chalè ki nesesè pou bese tanperati 4 kg likid ki gen yon chalè espesifik 500 J/kg K soti nan 40 oC vin tounen 20 oC se…
A. 20 kJ
B. 30 kJ
C. 40 kJ
D. 50 kJ
E. 60 kJ
Diskisyon:
Li konnen :
Mas (m) = 4 kg
Chalè espesifik (c) = 500 J/kg K = 500 J/kg Co
Chanjman tanperati (delta T) = 40 oC - 20 oC = 20 Co
Mande :
Chalè (Q)
Jawab :
Fòmil Chalè :
Q = (m)(c)(delta T)
Q = (4)(500)(20) = 40.000 Joul = 40 kJ
kJ = kilo Joule
Repons ki kòrèk la se C.
5. Yon objè solid ki gen yon mas 2 kg chofe apati yon tanperati 30oC vin tounen 100oC, mande 7 × 10 chalè5 Joule. Chalè espesifik objè a se…
A. 400 J/kg K
B. 500 J/kg K
C. 700 J/kg K
D. 1000 J/kg K
E. 5000 J/kg K
Diskisyon:
Li konnen :
Mas (m) = 2 kg
Chalè (Q) = 7 × 105 J = 700.000 J
Chanjman tanperati (delta T) = 100 oC - 30 oC = 70 Co
Mande :
Chalè espesifik (c) ?
Jawab :
c = Q / m T
c = 700.000 J / (2 kg)(70 Co) = 700.000 J / 140 kg Co
c = 5000 J/kg Co
c = 5000 J/kg K
Repons ki kòrèk la se E.
