Question

Volumul unei cantitati de hidrogen de masa m, aflate initial la temperatura t1, creste de k ori prin dilatare izobara . Aflati:
a)lucrul mecanic L efectuat de gaz
b)caldura Q absorbita
c)variatia ΔU a energiei interne
Aplicatie: m=2g t1=27 grade celsius k=3

Answer 1

T1=300k T2=3T1 m=0,002kg M=0,002kg/mol c=14300j/kg/k Delatarea izobara ne spune ca presiunea ramine constanta,iar volumul creste,,,in asa caz L=P*delta(V)=PV2-PV1 PV=niuRT Deci L=niuRT2-niuRT1=niuR(T2-T1)= mR(kT1-T1)/M=mRT1(k-1)/M L=8,3*300*2=4980 (j) c=Q/(m*delta(t)) Q=c*m*delta(t)=c*m*(T2-T1)=c*m*2*T1 Q=14300*0,002*2*300=17160 (j) Delta(U)=Q-L Delta(U)=17160-4980=12180 (j)