Work and Delta V
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Work and Delta V
Can someone confirm that work depends on delta V?
If volume is constant, delta V=0 so work =0?
If volume is constant, delta V=0 so work =0?
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Re: Work and Delta V
Ya, that's right! A system where there is no volume change is called an isochoric system and it's work is always 0!
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Re: Work and Delta V
Yes, work does depend on delta V because if we look at the equation w=P * delta V, an increase in delta V would lead to an increase in the amount of work being done by or on the system.
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Re: Work and Delta V
When deltaV is equal to zero, work would also be zero. Looking at the work equation w = p*deltaV , if deltaV is zero then anything times zero will be zero.
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Re: Work and Delta V
Work does depend on delta V because the definition of work is the energy required to move an object a certain volume against a force. So, if there is no volume change, then work would be 0, which is shown by w=-Pex(delta V).
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Re: Work and Delta V
Yes you are correct!:) is there is not delta V then the work would equal zero as work is dependent on the volume of a system changing!
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Re: Work and Delta V
To follow up with this equation, how would we go about solving a problem with constant external pressure and temperature? Especially if one value isn't given.
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Re: Work and Delta V
Work depends on both pressure of the external force and the volume change. If there is no external pressure, no work is done. This type of expansion is called free expansion, and it occurs in a vacuum. If no volume change takes place, then all energy input/output is being converted into/out of the kinetic energy of the molecules of the gas. This type of energy transfer is called isochoric.
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Re: Work and Delta V
Yes! In systems with no expansion or compression, there is no work done, so w=0 in these situations. Unless volume is changed, work is not done, and this is referred to as an isochoric system. You can refer to the equations for irreversible and reversible reactions to make this clear.
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Re: Work and Delta V
Yes you are correct. For a system of constant pressure, work = - P * deltaV. If deltaV were to change, then work will change, hence work is dependent on volume. If there is no change in volume then deltaV would equal 0, and by solving algebraically we would see that work would also equal 0.
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Re: Work and Delta V
Yes thats right. Only for systems at constant volume (delta V=0) is work equal to 0
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Re: Work and Delta V
Yup, if there is no volume change, no work is being done on the surroundings or system so w=0
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Re: Work and Delta V
Yep, if there is no volume change, then there is no work done by the system or on the system.
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Re: Work and Delta V
Yes I believe that when there is no volume chance there is no work done by system as well!
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Re: Work and Delta V
Yes in this class we are only focusing on work by expansion/reduction and if the volume is constant then we say that there is no work being donee.
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Re: Work and Delta V
even though there is no measurable change and in volume and no source of pressure isn't the act of expansion, means work is done BY THE SYSTEM
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