Consider the thermochemical equation for the combustion of acetone (C3H6O), the main ingredient in nail polish remover: C3H6O(l) + 4 O2(g) → 3 CO2(g) + 3 H2O(g) ΔH°rxn = -1790 kJ. If a bottle of nail polish remover contains 177 mL of acetone, how much heat is released by its complete combustion? The density of acetone is 0.788 g/mL.

Verified step by step guidance

Calculate the mass of acetone using its volume and density: mass = volume \times density.

Convert the mass of acetone to moles using its molar mass: moles = \frac{mass}{molar\ mass}.

Use the stoichiometry of the reaction to determine the heat released: \Delta H_{rxn} is given per mole of acetone.

Multiply the moles of acetone by the \Delta H_{rxn} to find the total heat released.

Ensure the units are consistent and the final answer is in kilojoules (kJ).

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Thermochemical Equations

Thermochemical equations represent the heat changes associated with chemical reactions. They include the enthalpy change (ΔH) which indicates whether a reaction is exothermic (releases heat) or endothermic (absorbs heat). In this case, the negative ΔH°rxn value of -1790 kJ signifies that the combustion of acetone releases 1790 kJ of energy per mole of acetone reacted.

Density and Volume Relationship

Density is defined as mass per unit volume and is crucial for converting between the volume of a liquid and its mass. In this problem, the density of acetone (0.788 g/mL) allows us to calculate the mass of acetone in the bottle by multiplying the volume (177 mL) by the density, which is essential for determining how many moles of acetone are present for the combustion reaction.

Mole Concept and Stoichiometry

The mole concept is fundamental in chemistry for quantifying substances. Stoichiometry uses balanced chemical equations to relate the amounts of reactants and products. By calculating the number of moles of acetone from its mass, we can use the stoichiometric coefficients from the thermochemical equation to find the total heat released during its complete combustion.

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