The heat of combustion of carbon to CO 2 is − 393.5 kJ/mol . The heat released upon formation of 35.2 g of CO 2 from carbon and oxygen gas is

Question

The heat of combustion of carbon to CO 2 ​ is − 393.5 kJ/mol . The heat released upon formation of 35.2 g of CO 2 ​ from carbon and oxygen gas is

TestHub · Accepted Answer

The combustion reaction of carbon is given by:

$C(s) + O_{2} (g) \to CO_{2} (g)$

The heat of combustion of carbon to $CO_{2}$ is $Δ H = - 393.5 kJ/mol$ .

Molar mass of $CO_{2} = 12 + 2 \times 16 = 44 g/mol$ .

Number of moles in $35.2 g$ of $CO_{2}$ is:

$n = \frac{35.2}{44} = 0.8 mol$

The enthalpy change for the formation of $0.8 mol$ of $CO_{2}$ is:

$Δ H = 0.8 mol \times (- 393.5 kJ/mol) = - 314.8 kJ \approx - 315 kJ$

The negative sign indicates that the heat is released during the process.

Answer: $- 315 kJ$

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