Skip to main content
Ch.4 - Chemical Reactions and Chemical Quantities
Chapter 4, Problem 67

The combustion of gasoline produces carbon dioxide and water. Assume gasoline to be pure octane (C8H18) and calculate the mass (in kg) of carbon dioxide that is added to the atmosphere per 10.0 kg of octane burned. (Hint: Begin by writing a balanced equation for the combustion reaction.)

Verified step by step guidance
1
Write the balanced chemical equation for the combustion of octane (C8H18). The general form of a combustion reaction is: hydrocarbon + oxygen (O2) ightarrow carbon dioxide (CO2) + water (H2O). For octane, the balanced equation is: 2 C8H18 + 25 O2 ightarrow 16 CO2 + 18 H2O.
Calculate the molar mass of octane (C8H18). Using the atomic masses from the periodic table (C = 12.01 g/mol, H = 1.008 g/mol), the molar mass of C8H18 = (8 \times 12.01) + (18 \times 1.008) g/mol.
Determine the moles of octane burned using the mass of octane and its molar mass. Moles of octane = mass of octane / molar mass of octane.
Use the stoichiometry of the balanced equation to find the moles of CO2 produced per mole of octane burned. From the balanced equation, 16 moles of CO2 are produced for every 2 moles of octane.
Calculate the mass of CO2 produced using the moles of CO2 and the molar mass of CO2 (C = 12.01 g/mol, O = 16.00 g/mol, so molar mass of CO2 = 12.01 + (2 \times 16.00) g/mol). Mass of CO2 = moles of CO2 \times molar mass of CO2. Convert this mass from grams to kilograms to find the mass of CO2 added to the atmosphere per 10.0 kg of octane burned.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

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

Combustion Reaction

A combustion reaction is a chemical process in which a substance (typically a hydrocarbon) reacts with oxygen to produce carbon dioxide and water. In the case of octane (C8H18), the balanced equation for its combustion is C8H18 + 12.5 O2 → 8 CO2 + 9 H2O. Understanding this reaction is crucial for determining the products and their quantities when octane is burned.
Recommended video:
Guided course
02:24
Combustion Apparatus

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced equation. It allows us to determine the relationships between the amounts of substances consumed and produced. In this problem, stoichiometry will be used to find out how much carbon dioxide is produced from burning a specific mass of octane.
Recommended video:
Guided course
01:16
Stoichiometry Concept

Molar Mass

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). For octane (C8H18), the molar mass is approximately 114.22 g/mol. Knowing the molar mass is essential for converting between mass and moles, which is necessary for applying stoichiometric calculations in the combustion reaction.
Recommended video:
Guided course
02:11
Molar Mass Concept
Related Practice
Textbook Question

Write the balanced chemical equation for the reaction of solid lithium with liquid water.

Textbook Question

Write the balanced chemical equation for the reaction of solid potassium with liquid water.

Textbook Question

Write the balanced equation for the reaction of hydrogen gas with bromine gas.

1
views
Textbook Question

Many home barbeques are fueled with propane gas (C3H8). What mass of carbon dioxide (in kg) is produced upon the complete combustion of 37.8 L of propane (approximate contents of one 5-gallon tank)? Assume that the density of the liquid propane in the tank is 0.621 g/mL. (Hint: Begin by writing a balanced equation for the combustion reaction.)

Textbook Question

Aspirin can be made in the laboratory by reacting acetic anhydride (C4H6O3) with salicylic acid (C7H6O3) to form aspirin (C9H8O4) and acetic acid (C2H4O2). The balanced equation is: C4H6O3 + C7H6O3 → C9H8O4 + C2H4O2 In a laboratory synthesis, a student begins with 6.00 mL of acetic anhydride (density= 1.08 g/ mL) and 2.50 g of salicylic acid. Once the reaction is complete, the student collects 1.82 g of aspirin. Determine the limiting reactant, theoretical yield of aspirin, and percent yield forthe reaction.

Textbook Question

The combustion of liquid ethanol (C2H5OH) produces carbon dioxide and water. After 4.62 mL of ethanol (density = 0.789 g/mL) is allowed to burn in the presence of 15.55 g of oxygen gas, 3.72 mL of water (density = 1.00 g/mL) is collected. Determine the percent yield for the reaction. (Hint: Write a balanced equation for the combustion of ethanol.)