Question

Gasoline is a mixture of hydrocarbons, but the heat released when it burns is close to that of octane, C₈H₁₈(l) ( ΔHf° = -250.1 kJ/mol). Research is underway to use H₂ from the electrolysis of water in fuel cells to power cars instead of gasoline.(a) Calculate ΔH° when 1.00 gal of gasoline (d = 0.7028 g/mL) burns to produce carbon dioxide gas and water vapor.

Answer 1

The value of ΔH° when 1.00 gal of gasoline burns to produce carbon dioxide gas and water vapour is -118. 167kJ.

Chemical reaction:

C8H18 + 25/2 O2 ----- 8CO2 +9H2O

Calculation of heat of reaction

∆H = ∆H°(product) - ∆H°(reactant)

∆H = ∆H° (CO2) +∆H°(H2O) - ∆H°(C8H18) -∆H° (O2)

As we know that,

∆H° (CO2) =-393.5 kJ/mol

∆H°(H2O) = - 241.836 kJ/mol

∆H°(C8H18) = -250.1 kJ/mol

∆H°(O2) = 0 kJ/mol

By substituting all the values, we get

∆H = 8(-393.5 kJ/mol) + 9(- 241.836 kJ/mol) +250.1 + 0

∆H = -5074.33 kJ/mol

Calculation of heat released when 1 gal of gasoline is burned

This can be given as

= (-5074.334 × 0.7028 × 1000 × 3.785)/114.23

By calculating we obtained

∆H° = -118.167kJ.

Thus, we calculated that the value of ΔH° when 1.00 gal of gasoline burns to produce carbon dioxide gas and water vapour is -118. 167kJ.

learn more about ∆H:

brainly.com/question/24170335

#SPJ4