p01_019.pdf

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Chapter 1 - 1.19

19. If M E is the mass of Earth, m is the average mass of an atom in Earth, and N is the number of atoms, then

M E = Nm or N = M E /m .Weconvertmass m to kilograms using Appendix D (1 u = 1 . 661

10 − 27 kg).

Thus,

N = M E

5 . 98

10 24 kg

10 − 27 kg / u) =9 . 0

10 49 .

(40 u)(1 . 661

m =