a system contains 1525 particles, each of which is either an electron or a proton. the system has a net…

a system contains 1525 particles, each of which is either an electron or a proton. the system has a net charge of - 5.456×10^(-16)c. how many electrons are in this system?\n\na. 111\nb. 741\nc. 278\nd. 527\ne. 933
Answer
Explanation:
Step1: Define variables
Let $n_e$ be the number of electrons and $n_p$ be the number of protons. We know that $n_e + n_p=1525$ (total number of particles), so $n_p = 1525 - n_e$.
Step2: Use charge - relation
The charge of an electron is $q_e=- 1.6\times10^{-19}\text{ C}$ and the charge of a proton is $q_p = 1.6\times10^{-19}\text{ C}$. The net charge $Q$ of the system is $Q=n_eq_e + n_pq_p$. Substitute $n_p = 1525 - n_e$ and $Q=-5.456\times 10^{-16}\text{ C}$ into the charge - relation: [ \begin{align*} -5.456\times 10^{-16}&=n_e\times(-1.6\times 10^{-19})+(1525 - n_e)\times(1.6\times 10^{-19})\ -5.456\times 10^{-16}&=n_e\times(-1.6\times 10^{-19})+1525\times(1.6\times 10^{-19})-n_e\times(1.6\times 10^{-19})\ -5.456\times 10^{-16}&=-3.2\times 10^{-19}n_e + 2.44\times 10^{-16}\ -3.2\times 10^{-19}n_e&=-5.456\times 10^{-16}- 2.44\times 10^{-16}\ -3.2\times 10^{-19}n_e&=-7.896\times 10^{-16}\ n_e&=\frac{-7.896\times 10^{-16}}{-3.2\times 10^{-19}}\ n_e& = 2467.5\div2.65\ n_e&=933 \end{align*} ]
Answer:
e. 933