## Chemistry and Chemical Reactivity (9th Edition)

Molecular weight of lithium carbonate: $2\times 6.94+12.011+3\times 15.999=73.89\ g/mol$ Mass fraction of lithium: $2\times 6.94/73.89\times 100\%=18.8\%$ From 73 million metric tons of lithium carbonate: $73\times 18.8/100 = 13.7$ million metric tons of lithium.