Consider the triple integral $\iiint (x,y,z) \, dV$, where $f(x,y,z)$ represents the density function and $G$ is the solid bounded by the sphere $x^2 + y^2 + z^2 = 3$. Find the mass using spherical coordinates. Write the limits in cylindrical and Cartesian coordinates to find the mass (Don't solve it). Write the expression for volume of the solid (Don't solve it).