When 0.40 mol of oxygen (`O_2`) gas is heated at constant pressure starting at `0^@`C, how much energy must be added to the gas as heat to triple its volume? (The molecules rotate but do not oscillate.)

Explanation

To solve the problem of how much energy must be added to 0.40 mol of oxygen gas at constant pressure to triple its volume, we will follow these steps:

### Step 1: Understand the relationship between volume and temperature at constant pressure.
At constant pressure, the volume of an ideal gas is directly proportional to its temperature in Kelvin. This relationship can be expressed as:
\[ V \propto T \]
Thus, if the volume triples, the temperature must also triple.

### Step 2: Convert the initial temperature to Kelvin.
...