Is this an input Energy?

[Visionary]

Say we have a burning match(Energy in the form of heat + light) and a barrel of Fuel.

I threw that match into the barrel got a HUGE explosion out of it!

 

The total inputted energy is the burning match + chemical potential energy in the fuel right?

The output would be a larger explosion( that is more heat and light)?

 

Im I getting this right?

Edited August 28, 2013 by Visionary

[Endercreeper01]

Ya

But the input energy must equal the energy from the explosion

[Visionary]

Well of course.

 

Ein = Eout

 

But the real world: Ein = Eout + losses

[Endercreeper01]

Well of course.

 

Ein = Eout

 

But the real world: Ein = Eout + losses

But the losses are part of the energy out

[studiot]

Before you can identify your input energy, you must specify your system, system boundary and system process.

 

Input energy is defined as energy that crosses the system boundary during the system process.

 

So if your system is the barrel of fuel, than no, the chemical energy stored in the fuel is not input energy it is internal energy.

[Visionary]

What I meant by input energy is the total amount of energy inputted to give out a certain output.

The output Im referring to is the large explosion.

I assume the internal energy is like a stored energy that is converted to give an output, in our case the internal energy we can categorize it as "input".

[studiot]

If you wish to create a new system of thermodynamics based on your own private definitions, you will find it very hard in this world.

 

Better to learn and use the established ones.

[Visionary]

Okay,

We got off wrong here. Let's go back, so the burning match is what kind of energy?

And the internal energy is the fuel? The output would be = the match + internal energy of the fuel?

Studiot your point was not very clear.

Please clarify.

[studiot]

First we divide the universe into two parts.

 

The system and the rest of the universe.

 

The rest of the universe is usually called the surroundings or the environment.

 

Dividing the two we have the system boundary.

For instance you might choose the walls of the fuel barrel as your system boundary, the contents of the barrel as the system.

 

Work is done when the system boundary is displaced.

If the system expands the system does work on the rest of the universe.

If the system contracts the rest of the universe does work on the system.

 

This is one form of energy flow across the system boundary.

 

Heat input (or output) is another

 

Electrical energy is another

 

and so on.

 

Any system already contains energy stored up in chemical bonds, pressure, and so on. This pre-existing store is called internal energy and changes often result in changes to the internal energy.

The internal energy is balance sheet of all forms of energy already within the system.

Any new energy added to the system as a result of the system process adds to the internal energy in some way.

Any energy output by the system is subtracted from the internal energy.

 

This leads to the First Law or law of conservation of energy.

 

Change in internal energy = Work done on the system plus heat added plus other energy added

 

This change can be positive or negative, negative indicating that energy leaves the system.

 

In your case, initially the combustion energy of the match is input to the system, slightly increasing its internal energy.

The resultant explosion releases chemical bond energy as kinetic energy (pressure) of the combustion gasses which rapidly leave the system in the explosion.

 

Does this help?

Edited August 29, 2013 by studiot