Skip to main content
Ch.10 - Gases
Chapter 10, Problem 82c2

(c) Calculate the most probable speeds of Cl2 molecules at 300 K.

Verified step by step guidance
1
Identify the formula for the most probable speed of a gas molecule, which is given by \( v_p = \sqrt{\frac{2kT}{m}} \), where \( v_p \) is the most probable speed, \( k \) is the Boltzmann constant, \( T \) is the temperature in Kelvin, and \( m \) is the mass of a single molecule.
Convert the molar mass of \( \text{Cl}_2 \) from grams per mole to kilograms per molecule. The molar mass of \( \text{Cl}_2 \) is approximately 70.9 g/mol. Use Avogadro's number \( 6.022 \times 10^{23} \) to find the mass of one molecule.
Substitute the values into the formula: \( k = 1.38 \times 10^{-23} \text{ J/K} \), \( T = 300 \text{ K} \), and the calculated mass of a \( \text{Cl}_2 \) molecule.
Calculate the expression under the square root to find the most probable speed.
Ensure the units are consistent throughout the calculation to obtain the speed in meters per second (m/s).

Verified Solution

Video duration:
3m
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.

Kinetic Molecular Theory

Kinetic Molecular Theory explains the behavior of gases in terms of particles in constant motion. It posits that the temperature of a gas is directly related to the average kinetic energy of its molecules. This theory helps in understanding how temperature influences the speed of gas molecules, which is crucial for calculating the most probable speed.
Recommended video:
Guided course
01:19
Kinetic Molecular Theory

Most Probable Speed

The most probable speed of gas molecules is the speed at which the largest number of molecules are moving at a given temperature. It can be calculated using the formula v_mp = sqrt(2kT/m), where v_mp is the most probable speed, k is the Boltzmann constant, T is the temperature in Kelvin, and m is the mass of a molecule. This concept is essential for determining the speed of Cl2 molecules at 300 K.
Recommended video:
Guided course
01:35
Most Probable Speed Example

Molar Mass and Gas Constant

Molar mass is the mass of one mole of a substance, which is critical for converting between grams and moles in calculations. For Cl2, the molar mass is approximately 70.9 g/mol. The gas constant (R) is used in various gas equations and relates to the behavior of gases under different conditions, aiding in the calculation of molecular speeds.
Recommended video:
Guided course
00:51
The Ideal Gas Law: Molar Mass
Related Practice
Textbook Question

(b) Calculate the rms speed of NF3 molecules at 25 °C.

1243
views
Textbook Question

(c) Calculate the most probable speed of an ozone molecule in the stratosphere, where the temperature is 270 K.

521
views
Textbook Question

(c) Calculate the most probable speeds of CO molecules at 300 K.

123
views
Textbook Question

Which one or more of the following statements are true? (a) O2 will effuse faster than Cl2. (b) Effusion and diffusion are different names for the same process. (c) Perfume molecules travel to your nose by the process of effusion. (d) The higher the density of a gas, the shorter the mean free path.

1028
views
Textbook Question

At constant pressure, the mean free path 1l2 of a gas molecule is directly proportional to temperature. At constant temperature, l is inversely proportional to pressure. If you compare two different gas molecules at the same temperature and pressure, l is inversely proportional to the square of the diameter of the gas molecules. Put these facts together to create a formula for the mean free path of a gas molecule with a proportionality constant (call it Rmfp, like the ideal-gas constant) and define units for Rmfp.

951
views
Textbook Question

Hydrogen has two naturally occurring isotopes, 1H and 2H. Chlorine also has two naturally occurring isotopes, 35Cl and 37Cl. Thus, hydrogen chloride gas consists of four distinct types of molecules: 1H35Cl, 1H37Cl, 2H35Cl, and 2H37Cl. Place these four molecules in order of increasing rate of effusion.

1411
views