Answer to Question #266975 in General Chemistry for kaltook

Question

How much heat (in kJ) is released when 15.0 L of CO at 85°C and 112 kPa reacts with 18.5 L of H2 at 75°C and 744 torr?

Answer 1

$CO+2H_2\to CH_3OH$

$V_{CO}=15L=0.015m^3$

$P=112000Pa$

$T=85^0C=358,15K$

$PV = nR T$

$n=(PV)/(RT)$

$n= (1120000,015)/(8,314358,15)$

n(CO)=0,564mol

$V_{CO}=18,5L=0,0185m^3$

$P=744torr=99191,84Pa$

$T=75^0C =348,15K$

$PV =n RT$

$n=(PV)/(RT)$

$n=(99191,840,0185)/(8,314348,15)$

$n(H_2)=0,634mol$

It can be seen that $H_2$ is the limiting reactant

$n(CH_3OH)=1/2n(H_2)=1/20,634MOL=0,317mol$

$\Delta H_{rxn}=\Delta H_f(CH_3OH)-\Delta H_f(CO)=-238,6-(-110,5)=-128,1kJ/mol$

$E=\Delta H_{rxn}\times n =-40,6kJ$