Mass of the Sun = 1.989 x 10^30 kg

Mass of Hydrogen Atom = 1.00794 grams

If we assume the Sun is made totally of hydrogen, how many hydrogen atoms are contained within the Sun? If the Sun converts hald of these hydrogen atoms into helium over its lifetime of about ten billion years, how many hydrogen atoms are converted per second?

1 answer

1.989*10^30 /(1.00794*10^-3)
= 1.973 * 10^33

half converted = .9867*10^33 converted

ten billion = 10^10 years

10^10y * 365d/y *24h/d*3600s/h = 3.154*10^17 seconds

so
.9867*10^33 converted/3.154*10^17 seconds
= .3128*10^16
= 3.128 * 10^15