## General, Organic, and Biological Chemistry: Structures of Life (5th Edition)

a. $SO_2$ and $O_2$: $$\frac{ 2 \space moles \space SO_2 }{ 1 \space mole \space O_2 } \space and \space \frac{ 1 \space mole \space O_2 }{ 2 \space moles \space SO_2 }$$ $SO_2$ and $SO_3$: $$\frac{ 2 \space moles \space SO_2 }{ 2 \space moles \space SO_3 } \space and \space \frac{ 2 \space moles \space SO_3 }{ 2 \space moles \space SO_2 }$$ $O_2$ and $SO_3$: $$\frac{ 1 \space mole \space O_2 }{ 2 \space moles \space SO_3 } \space and \space \frac{ 2 \space moles \space SO_3 }{ 1 \space mole \space O_2 }$$ b. $P$ and $O_2$: $$\frac{ 4 \space moles \space P }{ 5 \space moles \space O_2 } \space and \space \frac{ 5 \space moles \space O_2 }{ 4 \space moles \space P }$$ $P$ and $P_2O_5$: $$\frac{ 4 \space moles \space P }{ 2 \space moles \space P_2O_5 } \space and \space \frac{ 2 \space moles \space P_2O_5 }{ 4 \space moles \space P }$$ $O_2$ and $P_2O_5$: $$\frac{ 5 \space moles \space O_2 }{ 2 \space moles \space P_2O_5 } \space and \space \frac{ 2 \space moles \space P_2O_5 }{ 5 \space moles \space O_2 }$$
1. Identify all pairs: a. We can find the mole-mole factors between: $SO_2$ and $O_2$, $SO_2$ and $SO_3$, $O_2$ and $SO_3$ . b. We can find the mole-mole factors between: $P$ and $O_2$, $P$ and $P_2O_5$, $O_2$ and $P_2O_5$. 2. Use the coefficients of the balanced equation to write the conversion factors. a. $2SO_2(g) + O_2(g) \longrightarrow 2SO_3(g)$ Thus, if we use 2 $SO_2$ moles, we will need 1 $O_2$ mole to react with it, and it will produce 2 $SO_3$ moles. 2 $SO_2$ moles = 1 $O_2$ mole 2 $SO_2$ moles = 2 $SO_3$ moles 1 $O_2$ mole = 2 $SO_3$ moles b. $4P(s) + 5O_2(g) \longrightarrow 2P_2O_5(s)$ Thus, if we use 4 $P$ moles, we will need 5 $O_2$ moles to react with it, and it will produce 2 $P_2O_5$ moles. 4 $P$ moles = 5 $O_2$ mole 4 $P$ moles = 2 $P_2O_5$ moles 5 $O_2$ mole = 2 $P_2O_5$ moles