has the greatest average speed at 355 K.
Further Explanation:
Gas is one of the states of matter. In gases, the atoms and molecules have space between them and can easily move over each other hence gases are compressible. Gases neither have fixed shape nor volume. It occupies the shape and volume of the container. The examples of matter that are gases are nitrogen and carbon dioxide.
The kinetic theory is based on the following postulates:
1. Gas molecules have a large collection of individual particles with empty space between them and the volume of each particle is very small as compared to the volume of the whole gas.
2. The gas particles are in straight-line motion or random motion until they are not collided with the wall of the container or with each other.
3. The collision between the gas particles and the wall of the containers are an elastic collision that means molecules exchange energy but they don’t lose any energy during the collision. So the total kinetic energy is constant.
The formula to calculate the average speed of the gas is as follows:
…… (1)
Here,
is the average speed of gas.
k is the Boltzmann constant.
T is the absolute temperature.
m is the molar mass of gas.
The average speed of all gases is calculated at 355 K. So all the quantities on the right-hand side of equation (1) becomes constant, except for m. So equation (1) becomes,
…… (2)
Equation (2) clearly indicates that the average speed of the gas is inversely proportional to the molar mass of the gas. Higher the molar mass of the gas, more will be its average speed and vice-versa.
The molar mass of 
is 18 g/mol.
The molar mass of Ne is 20.18 g/mol.
The molar mass of 
is 28 g/mol.
The molar mass of 
is 70 g/mol.
The molar mass of is the least among all the given gases. So according to equation (2), its average speed is the greatest.
Learn more:
1. What is the kinetic energy of electrons?
2. Calculate the frequency of yellow light:
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Ideal gas equation
Keywords: CH4, Ne, Cl2, C2H4, molar mass of gas, Boltzmann constant, temperature, average speed of gas, m, T, 18 g/mol, 70 g/mol, 20.18 g/mol, 28 g/mol.
