Skip to main content
Ch.10 - Gases
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
All textbooksBrown 14th EditionCh.10 - GasesProblem 72a3
Chapter 10, Problem 72a3

(a) What are the mole fractions of H2 in a mixture of 15.08 g of O2, 8.17 g of N2, and 2.64 g of H2?

Verified step by step guidance
1
Step 1: The first step is to convert the mass of each component to moles. This is done by dividing the mass of each component by its molar mass. The molar mass of O2 is 32.00 g/mol, N2 is 28.01 g/mol, and H2 is 2.02 g/mol.
Step 2: After converting the mass of each component to moles, add up the total number of moles in the mixture. This is done by adding the number of moles of O2, N2, and H2 together.
Step 3: The mole fraction of a component in a mixture is the number of moles of that component divided by the total number of moles in the mixture. So, to find the mole fraction of H2, divide the number of moles of H2 by the total number of moles in the mixture.
Step 4: The result from step 3 is the mole fraction of H2 in the mixture. This value is a ratio and does not have units.
Step 5: Remember that the mole fraction is a way of expressing the concentration of a component in a mixture. It tells us what fraction of the total number of moles in the mixture is made up by a particular component.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

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

Mole Concept

The mole concept is a fundamental principle in chemistry that relates the mass of a substance to the number of particles it contains. One mole of any substance contains Avogadro's number (approximately 6.022 x 10²³) of entities, whether they are atoms, molecules, or ions. This concept is essential for converting grams of a substance to moles, which is necessary for calculating mole fractions.
Recommended video:
Guided course
01:25
Mole Concept

Mole Fraction

Mole fraction is a way of expressing the concentration of a component in a mixture. It is defined as the ratio of the number of moles of a specific component to the total number of moles of all components in the mixture. Mole fractions are dimensionless and provide a useful means of comparing the relative amounts of different substances in a mixture.
Recommended video:
Guided course
00:36
Mole Fraction Formula

Mass to Moles Conversion

To calculate mole fractions, it is necessary to convert the mass of each component in the mixture to moles. This is done using the formula: moles = mass (g) / molar mass (g/mol). Knowing the molar masses of O₂, N₂, and H₂ allows for the determination of the number of moles of each gas, which is crucial for finding the total moles and subsequently the mole fractions.
Recommended video:
Guided course
02:28
Mass and Moles Conversion
Related Practice
Textbook Question
A rigid vessel containing a 3:1 mol ratio of carbon dioxide and water vapor is held at 200 °C where it has a total pressure of 202.7 kPa. If the vessel is cooled to 10 °C so that all of the water vapor condenses, what is the pressure of carbon dioxide? Neglect the volume of the liquid water that forms on cooling.
Textbook Question

(a) What are the mole fractions of N2 in a mixture of 15.08 g of O2, 8.17 g of N2, and 2.64 g of H2?

Textbook Question

(b) What is the partial pressure in atm of each component of this mixture if its held in a 15.50-L vessel at 15 °C?

Textbook Question
At an underwater depth of 100 m, the pressure is 1.106 MPa. What should the partial pressure of oxygen be in the diving gas for the mole fraction of oxygen in the mixture to be 0.21, the same as in air?
Textbook Question

(a) What are the mole fractions of O2 in a mixture of 15.08 g of O2, 8.17 g of N2, and 2.64 g of H2?

Textbook Question
A sample of 5.00 mL of diethylether 1C2H5OC2H5, density = 0.7134 g>mL2 is introduced into a 6.00-L vessel that already contains a mixture of N2 and O2, whose partial pressures are PN2 = 21.08 kPa and PO2 = 76.1 kPa. The temperature is held at 35.0 °C, and the diethylether totally evaporates. (b) Calculate the total pressure in the container.