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When does delta U equal zero?

Posted: Tue Feb 12, 2019 4:23 pm
What are the rules for delta U = 0? When does this happen? Under what circumstances?

Re: When does delta U equal zero?

Posted: Tue Feb 12, 2019 4:55 pm
whenever its stated that a reaction is isothermal (reversible or nonreversible) you can assume that delta U = 0

Re: When does delta U equal zero?

Posted: Tue Feb 12, 2019 5:58 pm
Since deltaU=3/2nRT, if the reaction is at constant temperature, the internal energy will be equal to zero

Re: When does delta U equal zero?

Posted: Thu Feb 14, 2019 11:21 am
When work =0 and it is a adiabetical process, meaning that q=0.

Re: When does delta U equal zero?

Posted: Fri Feb 15, 2019 8:48 pm
If the reaction is isothermal, delta U=0.

Re: When does delta U equal zero?

Posted: Sat Feb 16, 2019 11:40 am
In an isothermal reaction, delta U will be 0. Since this is the case, you will also know that q=-w or w=-q, so you can easily calculate one if you know the other.

Re: When does delta U equal zero?

Posted: Sat Feb 16, 2019 11:59 am
When a reaction is isothermal, delta U (internal energy) equals zero.

Re: When does delta U equal zero?

Posted: Sat Feb 16, 2019 3:07 pm
Do we assume isothermal, reversible, and at equilibrium are all synonymous in this class?

Re: When does delta U equal zero?

Posted: Sat Feb 16, 2019 4:39 pm
I'm not sure if we can equate isothermal to equilibrium.

Re: When does delta U equal zero?

Posted: Sat Feb 16, 2019 5:50 pm
deltaU=0 when there is a constant temperature, or when temperature is 0. This is because of the equation U=3/2nRT. If constant temperature, Tf-Ti=0. However, if temperature=o, the equation would equal zero instantly.

Re: When does delta U equal zero?

Posted: Sat Feb 16, 2019 7:10 pm
I would just like to add that while delta U equals zero in an isothermal process (or in any isolated system), the two have no change in U for different reasons. In an isothermal process, the energy exchanged as heat (q) equals the amount of work done by the system (q = -w) so any heat energy from the process is cancelled out by work, and consequently delta U is 0. In an isolated system, no energy (either as work or as heatI is transferred, so q=0, w=0, and delta U = 0.

Re: When does delta U equal zero?

Posted: Mon Feb 18, 2019 2:25 am
In an isothermal reaction then delta U is zero.

Re: When does delta U equal zero?

Posted: Mon Feb 18, 2019 9:50 am
This is for an isothermal reaction. (We can also infer from this that q=-w)

Re: When does delta U equal zero?

Posted: Wed Feb 20, 2019 1:38 pm
if the problem states that it is isothermal, q=0 and q=-w, since delta U = q+w, 0+0=0

Re: When does delta U equal zero?

Posted: Wed Feb 20, 2019 10:40 pm
amogha_koka3I wrote:Do we assume isothermal, reversible, and at equilibrium are all synonymous in this class?

I believe that we can assume (for this class) that isothermal also means reversible. I don't think we can assume it's at equilibrium though.

Re: When does delta U equal zero?

Posted: Wed Feb 20, 2019 10:44 pm
delta U is equal to zero when the reaction is isothermal, meaning temperature is constant.

Re: When does delta U equal zero?

Posted: Thu Feb 21, 2019 12:04 am
When the reactions says it is isothermal that means that the temperature is constant (iso=same). If this is the case then there is no change in the internal energy therefore U is 0.

Re: When does delta U equal zero?

Posted: Thu Feb 21, 2019 1:30 am
When the reaction is isothermal