The charge on the capacitor tabs has doubled. How did the electrical capacity of the condensate change?

The classic answer to this question: the capacity will not change, since its value does not depend on the charge on the capacitor plates.

Proof: We apply the formulas for the capacitance of the capacitor:

1) C = q / U, where C is the capacitance of the capacitor; q and U are the charge and voltage across the capacitor plates, respectively. With an increase of 2 times, the voltage on its plates will increase by 2 times, respectively, and the capacity will remain unchanged.

2) The capacitance of a capacitor depends on its size, the area of ​​its plates, S, and the distance between them – d, and also the material of the dielectric:

C = e * e0 * S / d.