8.103

[Mia Navarro 1D]

I am not sure where to begin when approaching this problem. What equation do you use and why? The solution manual is very vague.

[Chem_Mod]

For this problem we would use the equation U=3/2nRT. Internal energy (U) is the total of all the energy associated with the motion of the atoms or molecules in the system. This includes energy associated with translation, rotation, and vibration. For monoatomic gases, like Kr, the only contribution to the energy comes from translational kinetic energy. The equation for internal energy is derived from the equation for kinetic energy KE=1/2mv². Since you have three degrees of freedom (x,y,z), the total energy is 3/2nRT.

[Cassandra Mullen 1E]

To start, check out the box on Section 8.7 pg 277. It says that the molar internal energy of a monatomic ideal gas at temp. T= 3/2RT. The average kinetic energy can be found using this expression.