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An experiment is devised to determine the heat of combustion for a certain fuel. During the experiment, 15.9 moles of the fuel was burned at STP to heat 98.6 kg of water from 40.5 °C to 80.7 °C. What is the heat of combustion determined by this experiment?

User Gby
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1 Answer

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Answer:

-1.04 × 10⁶ J/mol

Step-by-step explanation:

According to the law of conservation of the energy, the sum of the heat released by the combustion and the heat absorbed by the water is zero.

Qcomb + Qw = 0

Qcomb = - Qw [1]

The heat absorbed by the water can be calculated using the following expression.

Qw = cw . mw . ΔT

where,

cw is the specific heat capacity of the water

mw is the mass of the water

ΔT is the change in the temperature

Qw = (4.184 J/g.°C) × 98.6 × 10³ g × (80.7°C - 40.5°C) = 1.66 × 10⁷ J

From [1]

Qcomb = - 1.66 × 10⁷ J

The heat of combustion for this fuel is:


(-1.66 * 10^(7) J )/(15.9mol) =-1.04 * 10^(6) J/mol

User Ahmed Ablak
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