The internal energy of a substance

Consider the following statements:
$(1)$ Joule-Thomson experiment is isoenthalpic as well as adiabatic.
$(2)$ $A$ negative value of $\mu_{JT}$ (Joule-Thomson coefficient) corresponds to warming of a gas on expansion.
$(3)$ The temperature at which neither cooling nor heating effect is observed is known as inversion temperature.
Which of the above statements are correct?

At equilibrium,all systems are closed systems. $A$ saturated solution of glucose in an open vessel is which type of system?

To calculate the amount of work done in joules during reversible isothermal expansion of an ideal gas,the volume must be expressed in

An ideal gas expands from $1 \times 10^{-3} \ m^{3}$ to $1 \times 10^{-2} \ m^{3}$ at $300 \ K$ against a constant external pressure of $1 \times 10^{5} \ Nm^{-2}$. The work done is:

What is a system? Explain the types of systems.