The dominant mechanism of nuclear fusion of hydro­gen to helium in the sun is believed to...

The dominant mechanism of nuclear fusion of hydro­gen to helium in the sun is believed to be

where the last reaction is electron-positron annihilation, v is a neutrino, and γ is a gamma-ray photon. (a) What is the overall reaction? What is the stoichiometric number of each step in the mechanism? (b) The isothermal ΔUm for this fusion reaction is −2.6 × 109 kJ/mol. The sun radiates 3.9 × 1026 J/s. How many moles of 4He are produced each second in the sun? (c) The earth is on the average 1.5 × 108 km from the sun. Find the number of neutrinos that hit a square centimeter of the earth in 1 s. Consider the square centimeter to be perpendicular to the earth-sun line.