CHEMISTRY COMMUNITY

What is the first law of thermodynamics? How is it used and why?

The first law of thermodynamics states that energy is never removed or destroyed, it is only transferred. This is helpful because we know that if energy (q) is leaving the system, it MUST be going into the surroundings. We can also use this law to make the statement that + q = - q. This essentially states the same thing –– heat is lost from one region, but it must go into somewhere else.

Hope this helped!

Jarrett Peyrefitte 2K wrote:What is the first law of thermodynamics? How is it used and why?

Also, the equation for the first law of thermodynamics is
Delta U=w+q
This equation can have various ways of being expressed depending on the surroundings (whether pressure is constant ext..)

The first law mostly concerns that how in an isolated system, and how its internal energy is always constant

The 1st law of thermodynamics is conservation of energy, so the energy of an isolated system must remain constant. This gives delta u = q + w = 0

states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy

Energy is never destroyed in an isolated system just changes form. So the energy you begin with will be there in the end in some form or another.