Question

O cantitate constanta de gaz ideal biatomic este incalzita izobar absorbind caldura Qp=700 J si apoi racita izocor pana la temperatura initiala.Calculati:a)Caldura cedata de gaz la racirea izocora.b)Lucrul mecanic efectuat la incalzire pe intregul proces.c)Variatia energiei interne la incalzire si pe intregul proces.Va rog frumos.!

Answer 1

Se da:
Cv=5R/2
Cp=7R/2 (gaz biatomic)
Q1=700J
T1=T3
a)Q2=?J
b)L1,L=?J
c)ΔU1,ΔU=?J

Formule:
a)L2=0⇒Q2=ΔU2
Q2=Cv×ν×ΔT2
Q2=5×R×ν×(T3-T2)/2
Q2=5×R×ν×(T1-T2)/2

Q1=Cp×ν×ΔT1
Q1=7×R×ν×(T2-T1)/2
R×ν/2=Q1/7×(T2-T1)

Q2=5×Q1×(T1-T2)/7×(T2-T1)
Q2=-5×Q1/7

b)L1=p×ΔV1
L1=ν×R×ΔT1

Q1=Cp×ν×ΔT1
Q1=7×R×ν×ΔT1/2
ν×R×ΔT1=2×Q1/7 (1)

L1=2×Q1/7

L=L1+L2, iar d-ce L2=0:
L=L1

c)ΔU1=Cv×ν×ΔT1
ΔU1=5×ν×R×ΔT1/2, iar din (1)
ΔU1=5×Q1/7

ΔU=ΔU1+ΔU2

Din a): ΔU2=Q2
ΔU2=-5×Q1/7

ΔU=5×Q1/7-5×Q1/7
ΔU=0

Calcule:
a)Q2=-5×Q1/7=-5×700/7=-500J
b)L1=2×700/7=200J
L=200J
c)ΔU1=5×700/7=500J
ΔU=0J