To calculate the work done, we use the formula:

```

Work = Force × Distance

```

In this case, the force is 8 N and the distance moved is 7 meters.

Plugging these values into the formula, we get:

```

Work = 8 N × 7 m = 56 J

```

Therefore, the work done when an 8 N force moves a block 7 meters is 56 Joules.