Can the temperature of an isolated system of gas be changed?

The $P-V$ graph of an ideal gas cycle is shown. The adiabatic process is described by the region

In summer,when the valve of a bicycle tube is removed,the escaping air appears cold. Why?

In adiabatic compression, the decrease in volume is associated with

When a gas expands adiabatically,

When $2 \text{ moles}$ of a monatomic gas expands adiabatically from a temperature of $80^{\circ} C$ to $50^{\circ} C$,the work done is $W$. The work done when $3 \text{ moles}$ of a diatomic gas expands adiabatically from $50^{\circ} C$ to $20^{\circ} C$ is: (in $W$)