Skip to main content
Pearson+ LogoPearson+ Logo
Ch.10 - Gases: Their Properties & Behavior
All textbooksMcMurry 8th EditionCh.10 - Gases: Their Properties & BehaviorProblem 147a
Chapter 10, Problem 147a

Isooctane, C8H18, is the component of gasoline from which the term octane rating derives. (a) Write a balanced equation for the combustion of isooctane to yield CO2 and H2O.

Verified step by step guidance
1
Identify the reactants and products in the combustion reaction. The reactants are isooctane (C_8H_18) and oxygen (O_2), and the products are carbon dioxide (CO_2) and water (H_2O).
Write the unbalanced chemical equation for the combustion of isooctane: C_8H_18 + O_2 \rightarrow CO_2 + H_2O.
Balance the carbon atoms first. There are 8 carbon atoms in isooctane, so you need 8 CO_2 molecules: C_8H_18 + O_2 \rightarrow 8CO_2 + H_2O.
Next, balance the hydrogen atoms. There are 18 hydrogen atoms in isooctane, so you need 9 H_2O molecules: C_8H_18 + O_2 \rightarrow 8CO_2 + 9H_2O.
Finally, balance the oxygen atoms. Count the total number of oxygen atoms needed on the product side (8*2 from CO_2 and 9*1 from H_2O) and adjust the O_2 molecules accordingly on the reactant side.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
4m
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 reacts rapidly with oxygen, producing heat and light. In the case of hydrocarbons like isooctane, the products are typically carbon dioxide (CO2) and water (H2O). Understanding this type of reaction is essential for writing balanced equations for combustion.
Recommended video:
Guided course
02:24
Combustion Apparatus

Balancing Chemical Equations

Balancing chemical equations involves ensuring that the number of atoms of each element is the same on both sides of the equation. This is achieved by adjusting the coefficients in front of the reactants and products. A balanced equation reflects the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.
Recommended video:
Guided course
01:32
Balancing Chemical Equations

Stoichiometry

Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction. It allows chemists to calculate the amounts of substances consumed and produced in a reaction. In the context of combustion, stoichiometry helps determine the exact ratios of isooctane, oxygen, carbon dioxide, and water involved in the reaction.
Recommended video:
Guided course
01:16
Stoichiometry Concept
Related Practice
Textbook Question

When a gaseous compound X containing only C, H, and O is burned in O2, 1 volume of the unknown gas reacts with 3 volumes of O2 to give 2 volumes of CO2 and 3 volumes of gaseous H2O. Assume all volumes are measured at the same temperature and pressure. (a) Calculate a formula for the unknown gas, and write a balanced equation for the combustion reaction.

Textbook Question

Isooctane, C8H18, is the component of gasoline from which the term octane rating derives. (b) Assuming that gasoline is 100% isooctane, that isooctane burns to produce only CO2 and H2O, and that the density of isooctane is 0.792 g/mL, what mass of CO2 in kilograms is produced each year by the annual U.S. gasoline consumption of 4.6⨉1010 L?

Textbook Question

Isooctane, C8H18, is the component of gasoline from which the term octane rating derives. (d) How many moles of air are necessary for the combustion of 1 mol of isooctane, assuming that air is 21.0% O2 by volume? What is the volume in liters of this air at STP?

Textbook Question
The Rankine temperature scale used in engineering is to the Fahrenheit scale as the Kelvin scale is to the Celsius scale. That is, 1 Rankine degree is the same size as 1 Fahrenheit degree, and 0 °R = absolute zero. (b) What is the value of the gas constant R on the Rankine scale in 1L ~ atm2>1°R ~ mol2? (c) Use the van der Waals equation to determine the pressure inside a 400.0-mL vessel that contains 2.50 mol of CH4 at a temperature of 525 °R. For CH4, a = 2.253 1L2 ~ atm2>mol2 and b = 0.04278 L>mol.