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Ch.6 - Thermochemistry
Chapter 6, Problem 51

How much work (in J) is required to expand the volume of a pump from 0.0 L to 2.5 L against an external pressure of 1.1 atm?

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Work in Thermodynamics

In thermodynamics, work is defined as the energy transferred when a force is applied over a distance. For gas expansion, the work done on or by the system can be calculated using the formula W = -P_extΔV, where P_ext is the external pressure and ΔV is the change in volume. The negative sign indicates that work is done by the system when it expands.
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Pressure-Volume Work

Pressure-volume work occurs when a gas expands or contracts against an external pressure. It is a common type of work in chemical processes, particularly in engines and pumps. The work done can be expressed in units of energy, such as joules, and is directly related to the pressure exerted and the change in volume of the gas.
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Unit Conversion

In this problem, it is essential to convert pressure from atmospheres to joules. The conversion factor is 1 atm = 101.325 J/L. This conversion allows for consistent units when calculating work, ensuring that the pressure and volume are compatible in the formula used to determine the work done during the expansion.
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