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Review: Heat is best understood as
3kg of water at 30°C is mixed with 0.5 kg of ice at -7°c. The specific heat for water is 4.187 kJ/kg°C, for ice 2.108 kJ/kgC. Calculate the amount of heat it would take to bring the ice from -7°C to 0°C. use
The heat it takes to warm the ice to 0°C cools the 30° water. What is the new temperature of the water?
How much heat does it take to melt 0.5kg of ice using the latent heat of fusion for water 336 kJ/kg
Using the heat you just calculated from the melting ice, what is the temperature of the water now?
Now we are mixing two different masses of water at two different temperatures to find the thermal equilibrium. You can set this up as
where x is the final temperature. solve for x.
We have talked about the three laws of thermodynamics before, see if you can match them to their more thermodynamic-y wording.
| Stavka koja se može prevući | arrow_right_alt | Odgovarajuća stavka |
|---|---|---|
law 3 - you can't get out of the game | arrow_right_alt | heat added to the system = increase of internal energy +external work done by the system |
law 1 - you can't win | arrow_right_alt | Heat will never flow from cold to hot by itself |
Law 2 - you can't break even | arrow_right_alt | The entropy of a system at absolute zero is a well defined constant |
Read book pages 304-319 do you have any questions?
Vocab question 1 - Aidabatic process is one
vocab question 2 - a heat engine
Which type of system transfers heat from a colder reservoir to a hotter reservoir?
Internal Combustion Engine
Air Conditioner
Steam Turbine
Refrigerator
Heat Engine
Heat Pump
If work is done on a system, does the internal energy of that system increase or decrease?
What does it mean that when energy is transformed it becomes less useful?
What is the relationship between the second law of thermodynamics and entropy
When air is quickly compressed, why does its temperature increase?
you cannot cool a kitchen by closing doors and windows but leaving the refrigerator open, but you can heat a kitchen by closing doors and windows and leaving an oven open. What is the difference?
Water evaporates from a salt solution and leaves behind salt crystals that have a higher degree of molecular order than the more randomly moving molecules in the saltwater. Has the entropy principle been violated? why or why not?
Why is it that 7 is the most common number to come up when someone is rolling two dice? And what does that have to do with thermodynamics?
an engine's efficiency can be, at most, 100% and then only really in ideal physics land
A modern internal combustion engine has a theoretical efficiency of about 50%, but their actual efficiency is closer to 20-30%. What does that mean?
A carnot cycle operates between a heat reservoir of 300.0°C and ( -100.0°C). Calculate the ideal efficiency of the engine. give your answer in the form of a percentage with four significant digits.
Calculate the Carnot efficiency of an OTEC power plant that operates on the temperature difference between deep 4℃ and 25℃ surface water?