A gas expands by `0.5L` against a constant pressure of `1 atm`. Calculate the work done in joule and calorie.

Explanation

To solve the problem of calculating the work done by a gas that expands by 0.5 L against a constant pressure of 1 atm, we will follow these steps:

### Step 1: Identify the given values
- Change in volume (ΔV) = 0.5 L
- External pressure (P_external) = 1 atm

### Step 2: Use the formula for work done during expansion
For a gas expanding against a constant external pressure, the work done (W) can be calculated using the formula:
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