# Work

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Dasha.Work
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8bee930e-207e-11e6-9770-bc764e2038f2

The Work by a Gas calculator computes the amount of energy acting on an amount of gas based on external pressure and the change in volume.

INSTRUCTIONS: Choose units and enter the following:

• (P)  This is the external pressure on the system.
• (Vi)  This is the initial volume.
• (Vf)  This is the final volume.

Work (W):  The calculator returns the work done by or on the system in units of (Joules). However, this can be converted to compatible units (e.g. N•m) via the pull-down menu.

### The Math / Science

The  Work by a Gas calculator computes the amount of force it takes to displace an object, in chemistry's case the force is the external pressure of molecules exerting force on the system, and the displacement is the change of volume. Work equation is used in the Internal energy equation[3].  If work is positive then the system does the work, if the work is negative then the work is done on the system.

The work equation is calculated by

W = -P * ΔV

where :

• W is the work done by or on the system in units of (Joules)
• P is the external pressure on the system in units of (Pa)
• ΔV is the change in volume[2] in units of (m3)

A more general representation of this work= force*distance relationship integrates the force applied over the distance spanned.

## References

[2] Whitten, et al. 10th Edition. Pp. 571

This equation, Work, is listed in 1 Collection.