Answer
a) $446.1\ g/mol$ b) $188.2\ g/mol$ c) $324.4\ g/mol$
Work Step by Step
Atomic weights: $Fe: 55.845u,\ O: 15.999u,\ S: 32.06u,\ N: 14.007u,\ C: 12.011u,\ H: 1.008u$
a) $Fe(C_6H_{11}O_7)_2$:
1 Fe + 12 C + 22 H + 14 O: $55.845+12\times12.011+22\times1.008+14\times15.999=446.1\ g/mol$
b) $CH_3CH_2CH_2CH_2SH$:
4 C + 10 H + S: $4\times12.011+10\times1.008+32.06=90\ g/mol$
c) $C_{20}H_{24}N_2O_2$:
20 C + 24 H + 2 N + 2 O:
$20\times 12.01+24\times1.008+2\times14.007+2\times15.999=324.4\ g/mol$
