Question

V. Heat Content of Fuels Instructions: Consider the liquid fuel n-octane. Supplied below in the table are 1) the enthalpy of combustion, AH., 2) the molecular weight of n-octane, and 3) the density of n-octane. ostanee AH ERA SMOWA Density C&His(C 1 -5,074.9 kJ/mol 114.23 g/mol 0.703 g/mL 1. Compute the gravimetric heat content of n-octane. Show your work. 2. Compute the volumetric heat content of n-octane. Show your work. 3. Write the balanced formation reaction for one mole of n-octane. 4. Write the balanced combustion reaction for one mole of n-octane.

Answer 1

(1)

Gravimetric heat content of n-octane :

Heat released by combustion of 1 mole of fuel = 5074.9kJ/mol

Heat released by combustion of 1 gm = 5074.9kJ/mol / 114.23g/mol = 44.427kJ/g

= 44.43kJ/g

(2)

Volumetric heat content of n-octane :

Heat released by combustion of 1ml = 44.427kJ/g × 0.703g/ml = 31.2322kJ/ml

= 31.23 kJ/ml

(3)

8 C(s, graphite) + 9 H₂(g)  $\rightarrow$ C₈H₁₈(l)

(4)

C₈H₁₈(l) + (25/2) O₂$\rightarrow$ 8 CO₂ (g) + 9 H₂O(l)