Delta U = Q


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Drew Myers 4G
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Joined: Sat Aug 17, 2019 12:17 am

Delta U = Q

Postby Drew Myers 4G » Sun Feb 02, 2020 1:21 pm

When does delta U only equal to q (when does w = 0)?

Alex Chen 2L
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Joined: Wed Sep 18, 2019 12:21 am

Re: Delta U = Q

Postby Alex Chen 2L » Sun Feb 02, 2020 2:00 pm

When w = 0, it means the system has constant volume and no energy is being used for expansion/compression work. Therefore, the change in internal energy U only depends on the energy transferred through heat, q.

Matt F
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Joined: Sat Aug 17, 2019 12:17 am

Re: Delta U = Q

Postby Matt F » Sun Feb 02, 2020 2:31 pm

As mentioned above, delta U will be equal to only q when work (w) is equal to zero. This can be seen in a closed system with constant volume, as work is typically done due to compression or expansion (changes in volume).

Kaitlyn Ang 1J
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Re: Delta U = Q

Postby Kaitlyn Ang 1J » Sun Feb 02, 2020 2:31 pm

Adding to this, you know work = 0 when because so 0 for (aka there is no change in volume, aka the volume is constant) makes the entire work equation 0

Osvaldo SanchezF -1H
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Re: Delta U = Q

Postby Osvaldo SanchezF -1H » Sun Feb 02, 2020 2:34 pm

When there is no expansion or compression, then the system is doing no work or no work is being done on the system so therefore Work would equal to 0. This means that Delta H would only be impacted by (+/-)q.

Sydney Myers 4I
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Re: Delta U = Q

Postby Sydney Myers 4I » Sun Feb 02, 2020 4:05 pm

Kaitlyn Ang 1J wrote:Adding to this, you know work = 0 when because so 0 for (aka there is no change in volume, aka the volume is constant) makes the entire work equation 0



expanding on this, work is also 0 when pressure is 0, or when the system is in a vacuum.

MeeraBhagat
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Joined: Sat Aug 24, 2019 12:15 am

Re: Delta U = Q

Postby MeeraBhagat » Sun Feb 02, 2020 6:09 pm

Work=0 when volume is not changing or when pressure is zero (vacuum).

Hannah Pham
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Joined: Fri Aug 09, 2019 12:17 am

Re: Delta U = Q

Postby Hannah Pham » Sun Feb 02, 2020 6:55 pm

When W = 0 there is constant volume, in which there is no expansion or compression because that is when work is done.

Abigail_Hagen2G
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Re: Delta U = Q

Postby Abigail_Hagen2G » Sun Feb 02, 2020 7:14 pm

The work is zero when there is no expansion in volume or change in pressure, because otherwise it would affect the internal energy.


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