Which of the following equation is both physically and mathematically correct? Select all correct answers. A. $₁²80 = 0₂-Q₁ 3. f²dU =U₂-U₁ 1. C. f₁² dM = M₁-M₂ D. | dỤ=U,−U,

In thermodynamics, the thermodynamic properties are classified into two types of functions.

• There are some properties that depend only on the initial and final states. That is, these properties are independent of the path by which the change is brought. They are called state functions. The value of a state function when the system changes from the initial to the final state can be expressed as the difference between the property values at the final and initial states. 
• There are some properties that depend on the path by which the change is made.  They are called path functions. The value for a path function when the system changes from the initial to the final state cannot be expressed as the difference between those property values at the final and initial states.