Answer
There is a total of 0.991 mole of carbon atoms in 25.0 g of dipyrithione.
Work Step by Step
1. As we have calculated in 7.73b, there is 0.0991 mole of dipyrithione in 25.0 g of that.
2. Find the mole-mole conversion factors:
According to the subscript of $C$ in the chemical formula:
1 mole $C_{10}H_8N_2O_2S_2$ = 10 moles $C$
$\frac{ 1 \space mole \space C_{10}H_8N_2O_2S_2}{ 10 \space moles \space C}$ and $\frac{ 10 \space moles \space C}{ 1 \space mole \space C_{10}H_8N_2O_2S_2}$
3. Use the mole-mole conversion factors to calculate the amount of equivalent $C$ in moles:
$ 0.0991$ moles $C_{10}H_8N_2O_2S_2 \times \frac{ 10 \space moles \space C}{ 1 \space moles \space C_{10}H_8N_2O_2S_2} = 0.991$ moles C
