Termodynamics: heat supplied with loss of mass

• libelec
In summary, the conversation discusses finding the mass of liquid lead needed to heat up a certain amount of liquid water from one temperature to another, taking into account a loss of mass due to vaporization. The question is whether or not to include the heat of vaporization in the calculation, and it is determined that it should be included.
libelec

Homework Statement

Find the mass of liquid lead at fussion temperature needed to heat up 1kg of liquid water from 20ºC to 60ºC, considering P = 1 atm, and a loss of 100 mg of water due to local vaporization.

My question is: what do I do with that loss of mass? Do I calculate Q for m = (1000 - 0,1) g?

I'm really at loss with that.

Thanks.

Final mass of water is 1kg-100mg, no doubt about it. Question is whether heat of vaporization should be taken into account or not in heat balance. However, check if it matters - we are talking about 10-4 of the initial mass, most likely difference will be way below accuracy of the final result.

--

Yes, apparently I had to use that mass to calculate heat through the change of phase equation: Q = m*(delta)H.

Thanks.

1. What is thermodynamics?

Thermodynamics is the branch of science that deals with the relationship between heat, energy, and work. It describes how these factors interact and change in a system, and is essential in understanding many natural processes and phenomena.

2. What is meant by "heat supplied with loss of mass"?

This refers to a type of thermodynamic process where heat is added to a system, but at the same time, mass is lost from the system. This can occur in certain chemical reactions or when a substance undergoes a phase change, such as melting or evaporating.

3. How does the loss of mass affect the thermodynamic system?

The loss of mass can have a significant impact on the thermodynamic system, as it changes the overall mass and composition of the system. This, in turn, can affect the system's temperature, pressure, and other properties, leading to changes in the system's overall behavior.

4. Can the first law of thermodynamics be applied to systems with mass loss?

Yes, the first law of thermodynamics, which states that energy cannot be created or destroyed but can only be transferred or converted, still applies to systems with mass loss. The energy lost due to the loss of mass is accounted for in the overall energy balance of the system.

5. How is the second law of thermodynamics related to the concept of heat supplied with loss of mass?

The second law of thermodynamics states that the total entropy of a closed system always increases over time. In the case of heat supplied with loss of mass, this increase in entropy is due to the loss of mass and the associated increase in disorder or randomness. This process is irreversible and leads to a decrease in the efficiency of the system.

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