Using the following equation for the combustion of octane, calculate the heat associated with the combustion of 100.0 g of octane assuming complete combustion. the molar mass of octane is 114.33 g/mole. the molar mass of oxygen is 31.9988 g/mole.
2 c8h18 + 25 o2 → 16 co2 + 18 h2o δh°rxn = -11018 kj
a) -535.4 kj
b) -4819 kj
c) -602.3 kj
d) -385.5 kj
e) -11018 kj

The heat associated with the combustion of 100.0 g of octane, assuming complete combustion, is B) -4819 kJ.

Let's consider the following thermochemical equation.

2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O ΔH°rxn = -11018 kJ

First, we will convert 100.0 g of octane to moles using its molar mass (114.33 g/mol).

According to the thermochemical equation, 11018 kJ of heat are evolved when 2 moles of octane are combusted. The heat associated with the combustion of 0.8747 moles of octane is:

The heat associated with the combustion of 100.0 g of octane, assuming complete combustion, is B) -4819 kJ.

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B) -4819 kJ

Explanation:

The balanced reaction for combustion of octane is:

To calculate the number of moles, we use the equation:

given mass of octane = 100.0 g

Molar mass of octane = 114.33 g/mol

Putting in the values we get:

According to stoichiometry:

2 moles of octane give heat = -11018 kJ

Thus 0.8747 moles of octane give =

Thus -4819 kJ of heat is released by 100.0 g of octane assuming complete combustion.

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the correct answer is a