Find the net charge of a system consisting of 6.16×106 electrons and 7.68×106 protons. Express your answer using three significant figures. Qnet = 2.43×10−13 C

2.43 * 10^(-13) C

Explanation:

The net charge of the system is given as the sum of the total charge of the electrons and the charge of the protons.

Qnet = (Ne * Qe) + (Np * Qp)

Ne = number of electrons = 6.16 * 10^6

Np = number of protons = 7.68 * 10^6

Charge of an electron = -1.602 * 10^(-19) C

Charge of a proton = 1.602 * 10^(-19) C

Qnet = (6.16 * 10^6 * -1.602 * 10^(-19)) + (7.68 * 10^6 * 1.602 * 10^(-19))

Qnet = -9.87 * 10^(-13) + 12.30 * 10^(-13)

Qnet = 2.43 * 10^(-13) C

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.