Question

The 14C isotope is found once for every trillion Carbon atoms. The Earth’s atmosphere has a density of about 10^-3 that of water (which is 1 g/cm3 ) and covers the Earth’s surface (radius 6400 km) to a mean depth of about 5km (mean depth means that one-half the atmosphere is below this level). The atmosphere’s Carbon is almost all in CO2 and the CO2 concentration is now 410 parts per million (ppm) by volume (the way it is usually quoted) which corresponds to about 625 parts per million by mass. How many kilograms of 14C are there in the atmosphere? (Note: the 14C is only a fraction of the mass of each CO2 molecule).

Answer 1