How much effort goes into moving a charge of 9C between two sites with a potential difference of  19 V?

The amount of effort required to carry a unit charge from a reference point (or infinity) to a specific place in an electric field without causing acceleration is referred to as electric potential at that location.

V = W$/$Q

The amount of work required to transport a charged particle from infinity to a point in an electric field is referred to as the potential energy of that charged particle.

As a result:

Electric charge q = 9 C

Potential difference = V = 19 V

Work done  = charge x potential energy

W = 9 $\times$19

W = 171 J