Question

Heat Evolved During Combustion Consider the following reaction: 2 CO(g) + O2(g) 2 CO2(9) Use standard heats of formation from Zumdahl 'Chemical Principles' 8th ed. Appendix Four pp A19 - A21. How much heat is evolved when 1.071x101 moles of CO(9) is burned in excess oxygen. Answer to 4 sig figs. 1pts Submit Answer Tries 0/5 How much heat is evolved when 1.681x102 g of CO(g) is burned in excess oxygen. Answer to 4 sig figs. 1pts Submit Answer Tries 0/5 How much heat is evolved when 5.112 moles of CO2(g) is produced from the combustion of CO(g). Answer to 4 sig figs. 1pts Submit Answer Tries 0/5

Answer 1

Ans :

1)

2CO + O2 = 2CO2  $\Delta H = -566.0 KJ$

for 2 moles of CO 566.0 KJ of heat is evolved

so for 1.071 x 10¹ moles of CO , heat evolved will be :

= ( 1.071 x 10¹ mol x 566.0 KJ) / 2 mol

= 3030.93 KJ

2)

Mol CO = mass / molar mass

= (1.681 x 10² g) / 28.01 g/mol

= 6.001 mol

2 mol CO burns to evolve 566.0 KJ of heat

so 6.001 mol CO will release :

= ( 6.001 mol x 566.0 KJ) / 2 mol

= 1698.4 KJ

3)

2 mol of CO2 when formed , 566.0 kJ of heat is evolved

so when 5.112 moles of CO2 are formed , then the amount of heat evolved is :

= ( 5.112 mol x 566.0 KJ) / 2 mol

= 1446.7 KJ