Many portable gas heaters and grills use propane, C₃H₈(g), as a fuel. Using standard enthalpies of formation, calculate the quantity of heat produced when 10.0 g of propane is completely combusted in air under standard conditions.

Verified step by step guidance

1. Identify the balanced chemical equation for the combustion of propane: \( \text{C}_3\text{H}_8(g) + 5\text{O}_2(g) \rightarrow 3\text{CO}_2(g) + 4\text{H}_2\text{O}(l) \).
2. Determine the standard enthalpies of formation (\( \Delta H_f^\circ \)) for each substance involved in the reaction: \( \text{C}_3\text{H}_8(g) \), \( \text{O}_2(g) \), \( \text{CO}_2(g) \), and \( \text{H}_2\text{O}(l) \).
3. Use the formula for the standard enthalpy change of the reaction: \( \Delta H_{rxn}^\circ = \sum \Delta H_f^\circ (\text{products}) - \sum \Delta H_f^\circ (\text{reactants}) \).
4. Calculate the moles of propane in 10.0 g using its molar mass: \( \text{moles of } \text{C}_3\text{H}_8 = \frac{10.0 \text{ g}}{\text{molar mass of } \text{C}_3\text{H}_8} \).
5. Multiply the moles of propane by the \( \Delta H_{rxn}^\circ \) to find the total heat produced during the combustion.

Key Concepts

Combustion Reaction

A combustion reaction is a chemical process in which a substance reacts rapidly with oxygen, producing heat and light. In the case of propane (C3H8), the combustion reaction involves its reaction with oxygen to produce carbon dioxide and water. Understanding this reaction is crucial for calculating the heat released during combustion.

Standard Enthalpy of Formation

The standard enthalpy of formation (ΔHf°) is the change in enthalpy when one mole of a compound is formed from its elements in their standard states. This value is essential for calculating the heat produced in a reaction, as it allows us to determine the total energy change by using the enthalpies of the reactants and products involved in the combustion of propane.

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It is vital for determining the amount of heat produced from a specific mass of propane, as it allows us to convert grams of propane to moles and relate it to the heat released using the standard enthalpy of combustion.