## Chemistry and Chemical Reactivity (9th Edition)

a) $159.69\ g/mol$ b) $117.2\ g/mol$ c) $176.1\ g/mol$
Atomic weights: $Fe: 55.845u,\ O: 15.999u,\ B: 10.81u,\ Cl: 35.45u,\ C: 12.011u,\ H: 1.008u$ a) $Fe_2O_3$: 2 Fe + 3 O: $2\times55.845+3\times15.999=159.69\ g/mol$ b) $BCl_3$: B + 3 Cl: $10.81+3\times35.45=117.2\ g/mol$ c) $C_6H_8O_6$: 6 C + 8 H + 6 O: $6\times 12.01+8\times1.008+6\times15.999=176.1\ g/mol$