Yes it is a compound because mint ice cream and chocolate chips are being combined together.
The final volume : 3.4 L
<h3>Further explanation</h3>
Charles's Law
When the gas pressure is kept constant, the gas volume is proportional to the temperature

V₁=3300 ml
T₁=63 + 273=336 K
T₂=78+273=351 K
the final volume :

A solid dissolves in a liquid when it mixes completely with the liquid. ... Things which dissolve are called solutes and the liquid in which they dissolve is called a solvent to form a solution