The intensive property among these quantities is

For the isothermal expansion of an ideal gas:

Which of the following are extensive properties?

Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be .............. $Joules$.

Internal energy is an example of

Find the constant external pressure required to expand a gas from $2.5 \ L$ to $4.5 \ L$ if the amount of work done is $500 \ J$ at $298 \ K$. (in $bar$)