Answer
a) $20.47\times10^{23}$
b) $58.4\times10^{20}$
c) $137.9\times10^{23}$
d) $1.294\times10^{23}$
Work Step by Step
1 mole of any substance contains $6.022\times10^{23}$ entities.
Therefore,
a) 3.4 mol Cu contains
$3.4$ $\times$ $6.022\times10^{23}$ = $20.47\times10^{23}$ atoms of Cu.
b) $9.7\times10^{-3}$ mole C contains
$9.7\times10^{-3}\times6.022\times10^{23}$ = $58.4\times10^{20}$ atoms of C
c) 22.9 mole Hg contains
$22.9\times6.022\times10^{23}$ = $137.9\times10^{23}$ atoms of Hg.
d) 0.215 mole of Na contains
$0.215\times6.022\times10^{23}$ = $1.294\times10^{23}$ atoms of Na.
