How many atoms are in each elemental sample? Express your answer using two significant figures.
A. 4.8 mol Cu
B. 5.6x10^-3 mol C
C. 20.0 mol Hg
D. 0.285 mol Na

A. 2.9*10^24

B. 3.4*10^21

C. 1.2*10^25

D. 1.7*10^23

Explanation:

1 mol of any particle has 6.02*10^23.

A. 4.8 mol Cu* 6.02*10^23 (1/mol) ≈2.9*10^24

B. 5.6x10^-3 mol C *6.02*10^23 (1/mol) ≈3.4*10^21

C. 20.0 mol Hg*6.02*10^23 (1/mol)≈1.2*10^25

D. 0.285 mol Na*6.02*10^23 (1/mol)≈1.7*10^23

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