Topical Questions These questions are keyed to the major topics in the chapter. Usually...

Topical Questions

These questions are keyed to the major topics in the chapter. Usually a question that is answered at the back of this book is paired with a similar one that is not.

The mass of Earth’s atmosphere is 5.3 × 10¹⁵ metric tons. The atmospheric abundance of helium is 0.7 ppm when expressed as a fraction by mass instead of by volume, as in Table 10.1. How many metric tons of helium are there in the atmosphere? How many moles of helium is this?

Table 10.1