Question

Using the following equation for the combustion of octane, calculate the heat of reaction for 50.00 g of octane. The molar mass of octane is 114.33 g/mole. 2 C8H18 + 25 O2 -> 16 CO2 + 18 H2O Hrxn = -11018 kJ Using the following equation for the combustion of octane, calculate the heat of reaction for 50.00 of octane. The molar mass of octane is 114.33 . 2 + 25 16 + 18 = -11018 -2.410 kJ -6300 kJ -4820 kJ -2410 kJ

Answer 1

Answer : The heat of reaction is, -2407.43 KJ

Solution : Given,

$\Delta H^o_{rxn}=-11018KJ$

Mass of octane = 50 g

Molar mass of octane = 114.33 g/mole

First we have to calculate the moles of octane.

$\text{ Moles of octane}=\frac{\text{ Mass of octane}}{\text{ Molar mass of octane}}=\frac{50g}{114.33g/mole}=0.437moles$

The given balanced reaction is,

$2C_8H_{18}+25O_2\rightarrow 16CO_2+18H_2O$

From the reaction, we conclude that

2 moles of octane releases heat energy = -11018 KJ

0.437 moles of octane releases heat energy = $\frac{-11018KJ}{2moles}\times 0.437moles=-2407.43KJ$

Therefore, the heat of the reaction is, -2407.43 KJ