Answer
$ 6.32\times 10^{3}\ kg\ Li $
Work Step by Step
1. Use Avogadro's number to convert from atoms to moles of lithium. Then use the molar mass of lithium to convert from moles to grams of lithium. Finally, convert grams into kilograms.
2. $5.48\times10^{29}\ atoms\ Li\times\frac{1\ mol\ Li}{6.022\times 10^{23}\ atoms\ Li}\times\frac{6.94\ g \ Li}{1\ mol\ Li}\times\frac{1\ kg\ Li}{1000\ g\ Li}= 6.32\times 10^{3}\ kg\ Li $
