How Does Expansion Affect Internal Energy in a Monatomic Ideal Gas?

[Dan13]

Homework Statement

A monatomic ideal gas expands from 100cm³ to 200cm³ at a constant
pressure of 1.0 × 10⁵ Pa. Find the change in the internal energy of the gas.

Relevant Equations

Included in my attempt at a solution

Problem Statement: A monatomic ideal gas expands from 100cm³ to 200cm³ at a constant
pressure of 1.0 × 10⁵ Pa. Find the change in the internal energy of the gas.
Relevant Equations: Included in my attempt at a solution

 

[Chestermiller]

You almost had it, but not quite. You had $$\Delta U=\frac{C_v}{R}P\Delta V$$And we know that, for a monatomic gas, $$C_v=\frac{3}{2}R$$Therefore,...