7/24/2019 Parte1 Calor de Combustion

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Parte1.

Reaccin de combustin del acido benzoico.

C 6 H 5 COOH (s )+ 152

O 2 (g) 7 CO 2 (g)+3 H 2 O (l )

H = U +nRT

n = nproductos nreactivos = 7 15

2= 0.5 mol

H = 771270 cal /molT = 298.15 K R= 1.987 calmolK

molmolK 1.987 cal /(298.15 K )= 770973.788 cal /mol

771270 cal / ( 0.5 mol )

Uac . benzoico =

770973.788 cal /mol(1 mol122 g)= 6319.46 cal /g

Qganado = Qcedido

Qk +QH 20 = (Qcombustion +Qalambre +QHNO 3 )

K (T Ti )+ !H 20 CespH 20 (T Ti)= !ac . benzo UComb !alambre Ualambr e

K = !ac . benzo UComb !alambre Ualambre !H 2 OCespH 20 (T Ti)

(T Ti)

Datos:

!asaacido benzoico = 0.133 g Masa alambre =(Mi-Mf)=(0.0193-0.0134)=0.0059g

U alambre= 1400cal/g Masa H 20= 2000g Ti= 24.8 Tf= 2 .! U aci"# be$%#ic#=-0. 1cal/g

7/24/2019 Parte1 Calor de Combustion

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