You must show all mathematical steps leading to your answer

You must show all mathematical steps leading to your answer, especially for partial credits. Missing mathematical steps will not result in partial credit. A typical star like our sun with a mass of 2 Times 10^30 kg is mainly made of 75% hydrogen and 23% helium and 2% heavier elements. Sun produces energy through nuclear fusion of hydrogen in which hydrogen is converted into helium and energy. Scientists conclude that about 13% of hydrogen is used in star life time for nuclear fusion and it uses this fuel at a rate of 600 million tons per second. Given above information calculate the life span of the star. Extra Credit: How many hydrogen atoms Sun convert in 1 second? 2 points

Solution

Every reaction fuses 4 Hydrogen atoms:

(9.3 x 10³⁷ reactions/second) x (6.693 x 10^-27 kg/reaction) = 6.224 x 10¹¹ kg/s