A $5\mathrm{.}7$ g copper coin is given a charge of $4\mathrm{.}8109$ C$.$

$($a$)$

How many excess electrons are on the coin?

$3$e$10$

$3\mathrm{.}00$e$+10$

electrons

$($b$)$

By what percent do the excess electrons change the mass of the coin?

$4\mathrm{.}79$e$-16$

$4\mathrm{.}79$e$-16$

$\%$

$$