Answer:
The average kinetic energy of a gas molecule is 8.49 × 10⁻²¹ J
Step-by-step explanation:
According to Kinetic Molecular Theory, the average kinetic energy of gas molecules is a function only of temperature and is given by the equation:
![E=(3)/(2)kT](https://img.qammunity.org/2021/formulas/physics/high-school/89u2fjpwumd440wxpl8krl5a392l3gavq0.png)
![pV=nRT;\\T=(pV)/(nR)](https://img.qammunity.org/2021/formulas/physics/high-school/87991azsiwkgqhicptik57k4cy806z2gqs.png)
Substituting the value of T in the kinetic energy equation:
![E=(3kpV)/(2nR)](https://img.qammunity.org/2021/formulas/physics/high-school/lxmlp6k0ahgjab52nkbt2353tzzhwhweyf.png)
Where p is the pressure of the gas = 9 atm = 9 × 101325 pa
k is the Boltzmann’s constant = 1.38066 × 10⁻²³ J/K,
V is the volume of the gas = 7.1 L = 7.1 × 10⁻³ m³
n is the number of moles of the gas = 1.9 mol
R is the universal gas constant = 8.31451 J/K · mol.
E is the average kinetic energy of a gas molecule
Substituting values:
![E=(3kpV)/(2nR)=(3*1.38066*10^(-23)*9*101325*7.1*10^(-3))/(2*1.9*8.31451)=8.49*10^(-21)J](https://img.qammunity.org/2021/formulas/physics/high-school/6t1lejcmyg92louprfosjw1xvpaavvoonr.png)
The average kinetic energy of a gas molecule is 8.49 × 10⁻²¹ J